Plasma Lab for Applications in Sustainability and Medicine - ANTwerp

Research projects

Below, all current and previous research projects of our group are listed.  More details on our actual research can be found at “Research topics”.

Links to project networks:

  • ERC Synergy grant: SCOPE.
  • EOS (Excellence of Science) research project: PLASyntH2.

Ongoing projects

Plasma for environmental, medical, analytical chemistry and materials applications. 01/01/2025 - 31/12/2031

Abstract

Plasma is an ionized gas. It is the fourth state of matter, next to solid, liquid and gaseous state. It exists in nature, but it can also be generated in laboratories by applying electric fields or heat to a gas. It consists of gas molecules, but also many reactive species, like electrons, various types of ions, radicals and excited species. This highly reactive chemical cocktail makes plasma interesting for many applications. We are studying the underlying mechanisms in plasma, including the plasma chemistry, plasma reactor design and plasma‐surface interactions, by means of computer simulations and experiments, to improve the applications in: (1) sustainable chemistry (e.g., conversion of greenhouse gases and nitrogen fixation), (2) medicine (mainly cancer research), and (3) in micro-electronics (for microchip fabrication).

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  • Research Project

Efficient valorisation of CO2 and bio-waste for long-term energy storage using a microwave plasma torch and quenching using the reverse Boudouard reaction (EffiTorch). 01/10/2024 - 30/09/2028

Abstract

Now that renewable energy generation is already competitive in cost with electricity obtained from fossil fuels, the development of efficient long term energy storage methods seems crucial for a faster transition to a net-zero greenhouse gas emissions EU economy. Power-to-X methods are promising due to their negligible discharge rate but up to now all the efforts have been based on the use of H2 obtained by electrolysis, and the TEAs have shown that the high cost of the electrolysers hinders greatly its possibilities of industrial use. EffiTorch aims at developing an alternative breakthrough technology for Power-to-X based on the direct splitting of CO2, using an ultra-high temperature thermal plasma, with the simultaneous valorisation of low value bio-waste, leading to the efficient production of syngas. EffiTorch aims to reach carbon efficiencies higher than 90% and energy efficiencies higher than 60%, outperforming the best solutions available presently. Some of the research groups in Effitorch have a vast experience in CO2 splitting using Microwave (MW) plasma torches. Nevertheless, recently a compound approach that combines CO2 splitting by thermal plasmas with a quenching using the very endothermic reverse Bouduard reaction (RBR) has been developed in China that vastly improves the promising results obtained in the splitting of CO2 , while solving one of the yet unresolved issues, that of the efficient separation of the gases obtained. EffiTorch aims to explore the possibilities offered by a much improved version of the experimental set-ups used by the Chinese groups, including additional sophistications like the ultrasonic atomization of a bio-oil obtained by Hydrothermal Liquefaction (HTL) from sewage sludge, the use of high temperature reactors with plasma confinement and the implementation of a secondary heating of the plasma by induction with HF frequency (100-400 KHz), that could improve the energy efficiency and reduce costs.

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Alternative routes for basic chemicals production using hydrogen as feedstock (ALCHEMHY). 01/10/2024 - 30/09/2028

Abstract

ALCHEMHY aims to develop a set of innovative electrified processes to produce platform chemicals, particularly ammonia, i.e. a Magnetic-Heated Sorption-Enhanced Reactor (MSER) and Direct ElectroSynthesis of Ammonia (DESA); and methanol, i.e. a Small- Flexible Methanol Reactor (SFMR) and a Plasma-Catalytic Hydrogenation process (PCH). To this end, processes configuration will be optimised and novel materials and catalysts compatible with the electric input will be developed, optimising their performance, ramp-up times and enabling milder conditions. This will support the intensification and downscaling of the ammonia and methanol production, facilitating decentralised production integrated with downstream processes and renewable energy generation. This is crucial to decarbonise the production of both chemicals, as current production heavily relies on fossil natural gas for hydrogen generation. The 4 processes will be demonstrated at TRL 6 in relevant experimental facilities, while the technical and economic feasibility of the processes will be studied through a technoeconomic assessment (TEA) in two use cases: integrated ammonia and caprolactam production and refinery decarbonisation through CCU + a downstream methanol-to-olefin process. The processes upscaling, operation and TEA will be supported through dynamic modelling of the processes, generating a digital twin of the processes and a DSS to support H2 value chain design. The project consortium consists of 16 partners from 7 EU countries, with diversified expertise and knowledge in the addressed processes and access to the required lab and pilot infrastructure. The project will contribute to the development of a sustainable chemical industry, supporting the creation of green jobs and improving the competitiveness of European industries, while contributing to a more resilient and secure energy system for the EU, reducing its dependence on imported fossil fuels.

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What machine learning can bring to plasma catalysis: A generalized strategy to optimize methanol production from CO2 hydrogenation. 01/10/2024 - 30/09/2025

Abstract

Plasma-catalytic CO2 hydrogenation to methanol is a promising way to utilize CO2, owing to its potential to overcome traditional thermal barriers. It can help mitigate issues associated with climate change. However, one of the major challenges for plasma catalysis is to uncover the synergism between plasma and catalyst, to avoid trial-and-error experiments. Therefore, I will present a supervised learning (SL) framework to predict the methanol yield from experimental descriptors. Additionally, I will develop a so-called "methanol yield agent" by a reinforcement learning (RL) algorithm to perform effective actions on optimizing methanol production. Finally, I will experimentally validate the capability of my model to predict and regulate the methanol yield under varying catalyst compositions and reaction conditions to certify its implementation. I hope that my project will successfully demonstrate that a generalized, interpretable ML framework (SL model and RL strategy) offers a precious solution to guide plasma catalysis experiments and produce value-added compounds and renewable fuels for future large-scale industrial applications.

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Plasma Medicine against Actinic Keratosis (PlasmACT). 01/01/2024 - 31/12/2027

Abstract

The quality of human (and veterinary) health care systems substantially depends on key innovations. Often, these were driven by the field of physics, followed by interdisciplinary and inter-sectorial actions in engineering, chemistry, biology, and medicine, such as X rays in medical diagnostics, ionizing radiation in cancer treatment, and femtosecond lasers for precision surgery. Medical gas plasma technology was introduced to human health care a decade ago. Today, accredited medical plasma devices are in daily operation in dozen dermatology centers in middle Europe to improve wound healing. In addition, physical plasmas were shown to inactivate cancerous cells. Actinic Keratosis is a skin disease affecting millions of Europeans and making them prone to invasive and deadly skin cancer. Many of the available treatment options are associated with low efficacy, pain, risks, and/or high costs. Medical gas plasma technology is operated at body temperature and applied painlessly, cost-effectively, and without notable side effects. Gas plasma has been suggested to be active on high-grade cancer cells, but its activity against premalignant cells, as in Actinic Keratosis, is unknown. By using beyond state-of-the-art plasma multijet technology, the primary technical objective of this project (PlasmACT – Plasma against Actinic Keratosis) is to support skin cancer prevention by medical gas plasma therapy of Actinic Keratosis. PlasmACT does so by educating a new generation of application-oriented scientists that are exposed to questions and findings from different scientific fields (interdisciplinary from physics over chemistry and biology to medicine) and capable of addressing questions in view of both academic as well as business needs (inter sectoral) while incorporated in a vivid and productive environment across borders and cultures (international).

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Effect of non-thermal plasma in cancer treatment: Investigating the modulation of cell-to-cell communication via gap junctions in the tumour microenvironment. 01/01/2024 - 31/12/2027

Abstract

Despite the progress made on therapeutic strategies for cancer, the development of resistance is the most important challenge. A novel approach for cancer treatment is the induction of cell death by oxidative stress upon increasing the reactive oxygen and nitrogen species (RONS) levels in cancer cells. Non?thermal plasma (NTP) is a promising novel therapy based on the localized delivery of RONS, and it has strong anti-cancer effects in multiple cancer types. NTP can affect cell communication between cancer cells via specialized structures, called gap junctions (GJs). GJs can transport molecules (including death signals and RONS) between cells. However, normal cells of the tumour microenvironment (TME) can rescue cancer cells from cell death and promote resistance via GJs. To date, little is known about how NTP changes GJ cell communication in the TME. We aim to determine how NTP treatment affects GJ communication between cancer and other cells of the TME (such as stromal and endothelial cells). We will combine computer simulations and experimental work using well-established pancreatic ductal adenocarcinoma models. We will evaluate NTP effects on 2D, 3D, and in ovo cancer models, next to in silico analysis. Altogether, this will significantly advance our understanding of the mechanisms of action of NTP for cancer, in novel models that consider the role of other TME cells in the response and will allow the development of better therapies.

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Investigating the role of transient reactive species in plasma cancer treatment using a newly developed microfluidic platform (PlasmaFlow). 01/01/2024 - 31/12/2026

Abstract

Cold atmospheric pressure electrical plasmas generate highly reactive chemistry at room temperature. This plasma reactivity influences sensitive biological organisms and can be used in medical applications. Plasmas in cancer care have led to a reduction in tumor volume. However, the fundamental interaction processes of plasma with living organisms are still poorly understood. The aim of PlasmaFlow is to reveal the role of plasma reactive species in cancer treatment. We will develop a novel microfluidic-based platform that links plasmas with biomedical model systems by a flow-controlled chemistry. In this international collaborative project, a team of physicists, chemists, bio-medical researchers, and engineers combines experimental and modelling expertise. We will investigate the kinetics and dynamics of key processes in plasma-liquid-bio systems: In the proposed platform, a tailored reactive species composition will be delivered to cancer cell layers and 3D spheroid tumor models in a microfluidic chip, allowing us to quantify the cellular response. In this controlled environment, the plasma-liquid chemistry will be analyzed through 0D/2D chemical modeling, benchmarked by diagnostics of plasma parameters and reactive species in gas and liquid phase. The chemical modelling will include a numerical representation of the microfluidic channels. Our approach will form a key milestone to replace current empirical plasma treatment by knowledgebased, targeted plasma therapy.

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Support maintenance scientific equipment (Plasma Lab for Applications in Sustainability and Medicine - Antwerp - PLASMANT). 01/01/2024 - 31/12/2024

Abstract

In our research group PLASMANT we do research on plasmas for two main applications, i.e., sustainable chemistry and plasma medicine, by both experiments and modeling. For this purpose, we have several plasma reactors, which are powered by high-voltage power supply units. We also have several detection instruments, including several gas chromatographs, Fourier-transform infrared, non-dispersive infrared, mass spectrometer, and smaller gas sensors.

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Plasma-based CO2 conversion: energy-efficient separation for continuous CO production. 01/10/2023 - 30/09/2027

Abstract

This project studies plasma-based CO2 conversion in an industrial reactor (of D-CRBN, spinoff company of PLASMANT) and its subsequent separation towards CO production. The latter can be used by industry as a building block. The key research questions are: • How to boost reactor performance in an upscaled reactor, i.e., D-CRBN pilot with several reactors in parallel (in terms of conversion and energy efficiency), as compared to the lab scale (single) reactor of PLASMANT? • How do the various reactors in parallel influence each other? We need experimental results + deeper insights via Computational Fluid Dynamics simulations. • Which adsorbents show the highest purity of CO in the outlet stream? • Which technology is the most suitable to integrate with the plasma reactors: pressure swing adsorption (PSA) or temperature swing adsorption (TSA), keeping in mind that the latter can increase the overall energy efficiency by taking benefit of the hot gas flowing out of the plasma reactor? • How to integrate both parts into one industrial setup? We will need to create an engineering plan to construct such a system.

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Microwave plasma for efficient CO2 conversion: expanding the chemistry to improve the performance. 01/10/2023 - 30/09/2026

Abstract

Plasma-based CO2 conversion into value-added chemicals is very promising, as plasma can be powered by excess renewable energy. Nevertheless, its full potential has yet to be discovered. I will study a microwave plasma for this purpose, and focus on expanding the chemistry in three innovative ways. I will combine CO2 splitting with the addition of CH4 (another greenhouse gas) and/or H2O, to produce high-quality syngas (CO + H2) in one step. Moreover, I will introduce solid carbon after the plasma, to steer the selectivity towards the targeted products (pure CO, or pure syngas). Furthermore, I will optimize the performance with innovative reactor engineering, focusing on the gas flow dynamics and enabling new chemical pathways for the same reactant mixture. I will support my experiments with a thorough computational study of the chemical kinetics and fluid dynamics, both within the plasma reactor and the carbon bed. This will allow me to identify the key factors for reaction improvement without testing a wide range of conditions in the experiments, thus, avoiding a trial-and-error approach. The ultimate aim of my postdoctoral research is to achieve a deeper fundamental understanding of the mechanisms, as well as a full characterization of the plasma performance, which will help establish plasma technology at a commercial level and boost the transition towards a more sustainable energy economy.

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The installation, testing and demonstration of a new prototype of scrubber that recovers the ammonia by reaction of nitric acid produced on-site using a plasma reactor powered with renewable electricity. 01/06/2023 - 31/03/2025

Abstract

During this project, a new air scrubber concept is being developed that converts the ammonia from the ventilation air of stables into a concentrated solution of ammonium nitrate. Using a plasma reactor, air is converted into NOx gas, which reacts with water in a separate column to form nitric acid. The nitric acid solution is then used in a scrubber that captures ammonia from the ventilation air in a manner very similar to that of a traditional acid scrubber with sulfuric acid. The ammonia removal efficiency will therefore be very high (95-100%), just like with a scrubber with sulfuric acid. Because nitric acid is made from air instead of directly adding sulfuric acid, the resulting salt is ammonium nitrate (NH4NO3) instead of ammonium sulfate. This doubles the fertilization value as a molecule of nitrate is added for every molecule of ammonia. Furthermore, ammonium nitrate is also much more soluble than ammonium sulphate. This results in drain water with an N concentration that is up to 20 times higher than with a traditional acid air scrubber with sulfuric acid. This means a saving in water and storage tank volume, and an increased economic value of the drain water.

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MSCA4Ukraine Grant - Igor FEDIRCHYK. 01/05/2023 - 30/04/2025

Abstract

This project aims to develop a new process for NH3 cracking that may allow the implementation of an NH3-based H2 delivery infrastructure in Europe. The NH3 cracking will be studied by plasma technology, aiming for conversion above 99.5% and energy cost below 44 kJ/mol H2 achievable with the existing thermo-catalytic technology. The specific objectives are: 1) Investigation of optimal operating conditions in existing plasma reactors. Experiments will be performed in various plasma reactors available in PLASMANT. These systems performed favorably for other gas conversion applications but were not tested for NH3 cracking. We will evaluate their ability to reach the required NH3 decomposition rate, H2 yield, energy efficiency and energy cost for a wide range of plasma powers and flow rates. 2) Modelling the gas flow dynamics and plasma behaviour. To support the experiments, we will develop models for the gas flow dynamics and plasma behaviour inside the reactor for iterative testing and optimisation of improved reactor designs (cf. objective 4). 3) Modelling the plasma chemistry with a quasi-1D chemical kinetics model. We will elucidate the reaction kinetics behind NH3 cracking via plasma to better understand the underlying chemistry. A detailed kinetics model will offer new insight into the conversion process and allow further performance improvement. 4) Experimental evaluation of an improved plasma reactor and optimal operating conditions. Based on the experimental data (objective 1) and the models (objectives 2 and 3), we will develop an improved plasma reactor to decompose NH3 at lower energy cost than the existing plasma reactors.

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Circular CO2 conversion by means of atmospheric plasma (BluePlasma). 01/01/2023 - 31/12/2024

Abstract

Within this project, a larger R&D atmospheric plasma reactor will be constructed, aiming to increase the TRL of plasma technology to TRL4 - technology validated in a controlled environment. The optimal conditions to convert CO2 into CO using atmospheric plasma will be established by combining theoretical simulations with experimental observations in the R&D unit. The efficiency of the CO2 to CO conversion will be increased in several steps: • Step-wise integration of parallel plasma reactors on a single anode plate: Module 1 starting with 4 reactors with 20 L/min and 1kW of power per reactor (meaning 80 L/min and 4kW total). The target performance is 10% CO2 conversion (single-pass) and 30% energy efficiency. • In the next step, 7 reactors will be integrated on a single anode plate, in a hexagonal pattern. By this stage, the capacity of the plasma reactors will be 140 L/min of flow rate and 7kW of power (Module 2). The target performance is 15% CO2 conversion (single-pass) and 35% energy efficiency. • Module 3 will combine the power of Module 1 and 2 for a configuration of up to 11 reactors (220 L/min total capacity and 11kW power) in a hexagonal-like pattern, while maintaining strict power and efficiency requirement for each reactor node. The target performance is 20% CO2 conversion (single-pass) and 40% energy efficiency. • The CO production will be boosted by up to 50% by adding a carbon bed in the post-plasma stream, starting from module 1, but with sufficient capacity for Module 3. The target performance is 25% CO2 conversion (Boudouard reaction) and 50% boost in CO output. • An outflow-recirculation system will boost the CO2 conversion even further by increasing the residence time of unreacted gas in the main plasma reactor. Together with the carbon bed, this system can bring the overall CO2 conversion to at least 75%. • Novel structured catalysts will be used for plasma catalysis with a target lifetime of 1 year. This will further increase the CO2 conversion in the plasma phase by 10-20 %. The target is 90% CO2 reduction or more, in combination with the above-mentioned methods.

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Cracking of Green Ammonia to Hydrogen by Synergistic Combination of Thermocatalysis and Plasma Technology. 01/11/2022 - 31/10/2026

Abstract

Ammonia is a promising hydrogen carrier due to its high hydrogen density, but a missing link is an energy-efficient technology for ammonia cracking to produce hydrogen gas. The most explored option is thermocatalytic cracking, but this solution requires high temperatures to achieve near complete conversion, especially when using noble metal-free catalysts. Plasma cracking of ammonia is not limited by the same thermodynamic equilibrium as the applied electrical energy selectively heats electrons, due to their small mass, creating a thermal non-equilibrium. The highly energetic electrons can break up ammonia molecules and achieve higher conversions at lower bulk temperatures. The main downside of plasma cracking is the relatively high energy cost. During this PhD, a process, which combines the benefits of thermocatalytic and plasma cracking, will be explored. A packed bed reactor partly converts ammonia to H2 and N2 (>50 %). The outlet of the catalytic reactor is sent to the plasma reactor, where the remaining ammonia is converted as much as possible (aiming at > 99%). The first objective of this PhD is to develop a noble metal-free catalysts with high activity for ammonia cracking, without aiming at complete conversion. The second objective is to join the catalytic and plasma reactor and find the optimal combination of process parameters (temperatures, flow rates, conversion efficiencies, energy requirements) to minimize total energy cost and maximize synergy production rate.

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Unraveling the surface chemistry of icy dust particles in the interstellar medium. 01/10/2022 - 30/09/2026

Abstract

More than 200 different molecules have so far been identified in the interstellar space, ranging from H2 to complex organic molecules such as ethanolamine. In the extreme conditions of the interstellar space, gas phase reactions alone cannot explain their occurrence, and ice-covered dust particles are believed to play a crucial rol in their formation. At present, however, very little is known about the precise mechanisms of the interaction between the interstellar gas and the icy dust particles, and how these ice surfaces could "catalyse" the required chemical reactions. In this project, we will employ in-house developed state-of-the-art computational techniques to address these interactions. We will construct representative ice structures, calculate binding energies of astrochemically relevant molecules, and calculate free energy profiles and rate coefficients for a paradigmatic set of reactions. In collaboration with leading experts in the field, we will also assess the importance of these interactions on the resulting gas phase abundances, to enable accurate benchmarking against experimental data. This research carries the potential to change our perspective on how interstellar icy dust particles determine the chemical evolution of our universe.

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Cracking of green ammonia to hydrogen using innovative catalyst and adsorbent assisted plasma technology (HYPACT). 01/10/2022 - 31/03/2025

Abstract

Ammonia is a promising H2 carrier due to its high H2 density, but a missing link is an energy-efficient technology for ammonia cracking to produce ultrapure H2. The most explored option is thermo-catalytic cracking, which is a high temperature energy-intensive process, delivering H2 with undesired residual NH3. This project proposes a new ammonia cracking process based on integration of plasma technology with thermal catalysis and adsorptive purification, able to produce fuel cell grade H2 on large scale for handling large tonnages of ammonia for intercontinental import of H2.

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Carbon Neutral Milk (CANMILK). 01/09/2022 - 31/08/2026

Abstract

The challenge of agricultural GHG emissions is that they are highly diluted and originate from more than 10 million European farms. Thus, local emissions are small but the combined contribution on European level is ca. 10% of total GHG emissions. A significant portion of these is methane (ca 43 %), and most of that is produced by enteric fermentation, i.e. by belching cattle. Viable technical solutions do not exist for methane abatement, and new developments are urgently needed to meet the targets set by Methane Strategy, Farm to Fork Strategy and Fit for 55 legislation package for agricultural carbon neutrality in 2035. They must have high potential for commercialization, be efficient in methane abatement and costs must be affordable for the farmers. CANMILK will develop technology that is simple to use and has low maintenance, with overall cost below 80 €/t CO2-eq. A non-thermal plasma, or cold plasma, is today in everyday use e.g. in fluorescent lamps and ozone generators. CANMILK project will utilize this technology in a novel and innovative way in the fight against methane. The work is focused on the methane activation by plasma derived oxygen or hydrogen species enabling methane decomposition with the help of catalysts at mild conditions. As a result we expect to get 1) a simple and efficient equipment for methane abatement in dairy and meat cattle barns, 2) a good view of the socio-economic and environmental feasibility of plasma-based methane abatement and 3) increased public, scientific and industrial awareness of feasible solutions available for GHG abatement in agriculture. Our estimate for the efficiency of the CANMILK technology is 90% methane conversion, which in case of maximum utilization in barns would lead to total GHG abatement of ca. 140 Mt CO2-eq/a in Europe. This would have significant positive impacts to farmers, rural communities, consumers and industry in the transition of the European economy towards more carbon neutral, sustainable future.

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Plasma-based green hydrogen synthesis from hydrocarbons (PLASyntH2). 01/01/2022 - 31/12/2025

Abstract

Plasma-based H2 synthesis from hydrocarbons could be a complementary approach to water electrolysis, because it also uses renewable electricity and has no CO2 emission, and in addition, it can valorize CH4 and plastic waste, generate high value C-materials as side-product, and is thermodynamically more favourable. However, before exploiting this application, it is crucial to gain a better fundamental understanding of the plasma processes. This is exactly addressed in our project. We will perform green H2 synthesis experiments from various hydrocarbons and in several plasma types, in gas-phase and in contact with liquids, and develop a multi-diagnostics platform for time- and spatially-resolved characterization, as well as novel multi-dimensional, multi-scale models, to study the underlying mechanisms in all plasma systems. We will start with simple molecules, i.e., CH4 (gas-phase) and (m)ethanol (liquid-phase), and subsequently develop our methodologies to study H2 synthesis from alkenes (C3-C5 and higher) and styrene, as model systems for (both gas-phase and liquid-phase) pyrolysis products of plastic waste. Besides determining the H2 yield and energy consumption for all systems, and the detailed plasma diagnostics and modelling, we will also characterize the synthesized C, and target the latter as extra value-added product. The project outcomes will lay the basis for green H2 synthesis by plasma technology and will open up a new area in the field of plastic waste recycling.

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Modeling-based design of a rotating gliding arc plasmatron with gas quenching and heat recovery for conversion of CO2, CH4 and H2O 01/11/2021 - 31/10/2025

Abstract

CO2 and CH4 are two greenhouse gases that cause global warming. Hence, methods are being developed to convert these gases into renewable fuels or value-added chemical feedstock. Plasma technology is promising for this application. In this project I will investigate the bi-reforming of methane, in which CO2 and CH4 are converted together with H2O. This has the advantages of a better H2/CO ratio and no coke deposition compared to the dry reforming of methane (without H2O addition). The aim is to obtain as high as possible conversion and energy efficiency. To achieve this, I will design and study a novel rotating gliding arc plasmatron reactor, in which the gas mixture is heated before it enters the reactor and quenched afterwards, to avoid the recombination reactions. This research will be based on both experiments and modelling. In the experiments I will measure the actual conversion and energy efficiency for a wide range of conditions, as well as the gas temperature, vibrational temperature and arc dynamics. In addition, I will develop and combine five different models for reactor design improvement, and to investigate the gas flow dynamics and the chemical reactions taking place in and after the plasma. The combination of experiments and modelling should result in an optimal conversion of CO2, CH4 and H2O in the designed reactor and more insight into the properties of the plasma and the reaction mechanisms behind this conversion.

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Inducing angiogenesis in pancreatic cancer with cold atmospheric plasma to enhance drug delivery and efficacy. 01/11/2021 - 31/10/2025

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease with five-year survival rates of 2-9% and is predicted to become the third leading cause of cancer death in the EU by 2025. PDAC tumors show hypovascularity and vascular compression, causing chemoresistance, resulting from desmoplasia by pancreatic stellate cells (PSCs). Evidence has shown that a pro-angiogenic approach for PDAC increases drug delivery and efficacy, reducing tumor growth and metastasis. Cold atmospheric plasma (CAP) treatment is a novel and safe technology known to induce angiogenesis at low treatment doses. The objective and novelty of my project is to use mild CAP treatment to enhance the delivery and effect of chemotherapeutic drugs by inducing angiogenesis for a synergistic anti-cancer effect. The kINPen® plasma jet will be used to determine optimal CAP treatment conditions. Spheroid co-cultures of pancreatic cancer cells, PSCs and endothelial cells will be investigated. Gemcitabine will be used as chemotherapeutic drug and administration to 3D spheroids will be performed with the novel OrganoPlate® Graft, which allows vascularization of 3D in vitro models and increases the predictive power of in vitro work. Clinical efficacy will be evaluated by combining distal pancreatectomy with intra-operative CAP treatment and adjuvant chemotherapy in an orthotopic mouse model. This project will lead to a novel combinational treatment strategy for PDAC patients that can have partial or full resection.

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Catalysis for CCU: Valorization of CO and CO2 by carbon capture and utilization 01/01/2021 - 31/12/2025

Abstract

This Scientific Research Network is composed of researchers with diverse but complementary backgrounds in the CCU field. This critical pool of scientific expertise can accelerate the development of catalytic CCU technologies and provide advice to government, industrial and public sectors. Our goal is to build a CCU network relevant to the Flemish/European industrial landscape, focused on sharing best practices and knowledge; stimulating collaboration; exposing young researchers; creating a community; being a go-to place for expertise; and sharing resources that individual researchers and knowledge institutes lack. We believe the conditions are perfect to make Flanders the leading region for the development and implementation of CCU technologies in Europe.

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Power-to-olefins: Electrified steam cracking and plasma booster. 01/01/2021 - 31/12/2024

Abstract

The aim of this product is to drastically reduce CO2 emissions of olefin production by replacing the combustion furnaces, responsible for 90% of the CO2 emissions of this process, by a combination of two new electrified reactor concepts, i.e., an electrified rotor stator steam cracker, and a plasma-based ethylene booster. Our contribution is the latter concept, for which we will develop a kinetic model and a reactor model for process optimization.

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Research in plasma chemistry 01/02/2020 - 31/01/2027

Abstract

This research includes experiments and modeling on plasma used for environmental, green chemistry, and medical applications, more specifically: plasma-based gas conversion (CO2, N2, CH4) into value added compounds, as well as plasma for cancer treatment.

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Surface-COnfined fast-modulated Plasma for process and Energy intensification in small molecules conversion (SCOPE). 01/04/2019 - 31/03/2026

Abstract

This ERC Synergy project will introduce a ground-breaking approach to use renewable energy in three major industrial reactions: 1) N2 fixation, 2) CH4 valorization and 3) CO2 conversion to liquid solar fuels. We will use non-thermal plasma, which has large potential to convert these small (low reactive) molecules under near ambient temperature and pressure, particularly for distributed processes based on renewable energy. The new processes have drastically lower carbon footprint (up to over 90% with respect to current ones). Furthermore, CO2 conversion is crucial for a worldbased distribution of renewable energy. However, the selectivity and energy efficiency of plasma technologies for these reactions are too low, making radically new approaches necessary. The Project idea is to realize a highly innovative approach for non-thermal plasma symbiosis with catalysis. By inducing excited states in solid catalysts to work in synergy with the excited short-lived plasma species, we introduce a brand new idea for catalyst-plasma symbiosis. In addition, we introduce a fully new concept of nano-/micro-plasma array through a novel electrode design, to generate the plasma at the catalyst surface, thereby overcoming long distance transport. By embedding ferro-magnetic nano-domains in the catalyst support and inducing radiofrequency heating, we create fast temperature modulations directly at the catalyst active sites. Combining these elements, the project will overcome the actual limits and enhance the selectivity and energy efficiency to levels suitable for exploitation. This requires a synergy over different scale elements: nano at catalyst, micro at the level of modelling plasma generated species, milli at the reactor scale and mega at the plant level for sustainability-driven opportunity guidance and impact assessment by Life-Cycle-Assessment. The synergy value derives from the integration of the PI competencies over this entire dimensional-scale level.

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Computational modeling of materials: from atomistic properties to new functionalities. 01/01/2019 - 31/12/2028

Abstract

In this WOG, the overarching goal is to employ existing and develop new computational methodologies at the atomistic and molecular scale to model and simulate fundamental material properties to explore and understand novel material functionalities.

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Plasma for environmental, medical, analytical chemistry and materials applications. 01/05/2018 - 31/12/2024

Abstract

Plasma is an ionized gas. It is the fourth state of matter, next to solid, liquid and gaseous state. It exists in nature, but it can also be generated in laboratories by applying electric fields or heat to a gas. It consists of gas molecules, but also many reactive species, like electrons, various types of ions, radicals and excited species. This highly reactive chemical cocktail makes plasma interesting for many applications. We are studying the underlying mechanisms in plasma, including the plasma chemistry, plasma reactor design and plasma‐surface interactions, by means of computer simulations and experiments, to improve the following applications: (1) in materials science (for nanotechnology and microchip fabrication), (2) for analytical chemistry, (3) in environmental/energy applications (i.e., conversion of greenhouse gases and nitrogen fixation), and (4) for medicine (mainly cancer research).

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Inducing neoantigens with cold atmospheric plasma to improve cancer immunotherapy. 01/11/2023 - 31/10/2024

Abstract

Globally, cancer incidence is increasing, with 19.3 million new cases reported in 2020 and 9.96 million deaths. Immunotherapy was introduced as a new treatment and recently, neoantigens gained a lot of interest. Neoantigens are tumor-specific antigens that can increase the immune response against cancer cells. These can be induced not only by mutations, but also by post-translational modifications (PTMs), from which not much is yet known. Because neoantigens are unique to tumor cells, they are considered perfect targets for cancer treatment. However, multiple limitations still must be overcome, including the amount of neoantigens found in a tumor. Cold atmospheric plasma (CAP) is a novel cancer treatment method known to induce PTMs, immunogenic cell death, and increase immunogenicity. The novelty and objective of my project is to induce neoantigens with CAP to improve immunotherapy. I will use patient-derived organoids from head and neck cancer and pancreatic cancer. I will determine mutations and PTMs after treatment, by mass spectroscopy and sequencing. Next, I will generate a ranking of neoantigen candidates, induced due to the CAP treatment, with immunopeptidomics and in silico peptide prediction. I will test their immunogenicity in vitro through stimulation of T-cells with dendritic cells loaded with the candidate neoantigens. My project will lead to new targets for immunotherapy and lay the groundwork for combination treatments of immunotherapy and CAP.

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Molecular simulations of the interactions between reactive species and gap junctions for plasma-based cancer therapy. 01/10/2023 - 30/09/2024

Abstract

Cancer treatment based on cold atmospheric plasma (CAP) has been gaining increasing interest over the years. CAP generates a rich mixture of reactive oxygen and nitrogen species (RONS), which are able to interact with the surface of cancer cells. They induce oxidative damage to membrane lipids and proteins, leading to cell death. One set of proteins affected by RONS are the gap junctions (GJs) proteins. GJs are intercellular spaces formed by opposing hemichannels, consisting of two protein hexamers composed of connexins. GJs allow cell-to-cell communication and play an important role in transport of molecules between cells, including RONS, as well as for cell growth, mobility and differentiation. This allows GJs to act as tumor suppressors but also as promoters. Additionally, they play a key role in propagating oxidative stress-induced cell death to neighboring cells. Therefore, understanding the role of GJs in cancer and their mechanisms of action is critical for developing effective therapies, such as CAP. However, it is still unclear how RONS affects the anti- and pro-tumorigenic properties of GJs: How can RONS be transported through GJs? Do lipid and GJ oxidation affect the function of GJs? Therefore, I aim to unravel the effects of GJ-RONS interactions using molecular dynamics simulations, supported by experimental validation. I expect that modulation of the function of GJs can improve the efficacy of plasma treatment-based anti-cancer strategies, such as CAP.

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Plasma Reactors for Efficient Fertilizer Production Applied in a Real Environment (PREPARE). 01/11/2022 - 30/04/2024

Abstract

My project aims to demonstrate the proof of concept of new plasma reactors for sustainable and energy-efficient NOx production from air, as basis for green fertilizer production. Plasma is created by applying electricity, it is quickly switched on/off and has no economy of scale, so it is ideal in combination with renewable (intermittent) electricity, and thus, of interest for electrification of fertilizer production. This project originates from my ERC SyG, where we obtained record values in plasma-based NOx production and energy cost (EC). Now it is time to bring this into real application through optimization of the reactor design and its performance. We will build three different plasma reactor designs, based on innovative computer model predictions, and test the optimal matching to the power supply for maximum efficiency. We will also test the effect of quenching, heat recovery, pre-heating, gas recirculation and sorption materials, to further improve the performance in terms of NOx yields and EC. Subsequently, we will test the reactors in real world context, i.e., air with varying humidity and exploring the reactor robustness for both continuous long-term and intermittent operation. In the last two months, we plan demos for interested stakeholders, serving as real-life market analysis. Finally, we will perform a SWOT analysis, comparing the three reactors in terms of overall performance in real world context, to decide which reactor will be selected for up-scaling and potential commercialization. PREPARE aims to drive innovation for the application of HNO3 and NH4NO3 production, that is now mainly relying on non-sustainable resources. In addition, it can provide a solution to curb NH3 emissions from livestock and poultry farming, by letting the plasma-produced NOx react with the emitted NH3 to form NH4NO3. Hence, PREPARE provides an innovative route for greening up (1) the chemical/fertilizer-production industry and (2) the livestock and poultry farming sector.

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Better understanding of microwave plasma for CO2 conversion by modeling and experiments 01/11/2022 - 31/10/2023

Abstract

The aim of this project is to improve the energy efficiency of CO2 conversion and dry reforming of methane (DRM) in a microwave (MW) plasma by a combination of modeling and experiments to better understand the underlying mechanisms. The modeling is based on chemical kinetics modelling, which describes the detailed plasma chemistry, with special focus on the vibrational kinetics of CO2, as well as the interaction of the product mix (CO/O/O2 and unreacted CO2) with a carbon bed placed after the plasma reactor, to further enhance the CO2 conversion. The experiments are carried out at DIFFER (joint PhD under the co-supervision of Prof. Gerard van Rooij), and make use of laser scattering and optical emission spectrometry, to measure the actual plasma volume in the reactor, and the typical plasma characteristics. Specifically, it is investigated how CH4 addition to a CO2 plasma affects the plasma contraction and the underlying mechanisms. Also forward vs reverse vortex gas flow designs are compared, because the latter can give rise to less coking, hence better performance.

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Computational design of layered graphene oxide (GO) membranes. 01/10/2022 - 30/09/2023

Abstract

In recent years layered graphene oxide (GO) membranes showed immense potential to overcome the limitations of conventional membrane materials with superior water flux and intriguing physical/chemical properties. However, its practical applications is still questionable mainly due to its undesirable swelling in water. To address this issue, meticulous understanding on the effect of the oxygen containing functional groups on the performance of layered GO membranes is of utmost importance, which is not available in the existing literature. Intercalation of cations could enhance aqueous stability of layered GO membranes. Inspired by this, I propose that also the generation of hydronium ions inside the interlayer gallery would impart aqueous stability of GO membranes. Hydronium ions could be generated by the dissociation of water molecules using an external electric field. Additionally, by constructing a membrane from a heterostructure of GO and reduced GO nanosheets, a balance between water flux and aqueous stability could be obtained. This could also lead to a Janus membrane with different wettabilities on the same membrane structure which could be effective in the separation of various oil-water mixtures. In this proposal, we will investigate all these aspects using atomistic simulations with extensive collaborations with different experimental and theoretical groups.

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Energy‐efficient plasma conversion of greenhouse gases to methanol, the fuel of the future Acronym: OPTANIC. 01/09/2022 - 29/02/2024

Abstract

While the drastic climate actions across the globe are focusing on CO2 emissions, methane (CH4) poises an even greater threat in the nearby future. It is known that methane is nearly 25 times more potent as greenhouse gas compared to CO2. In this project, a concept for the production of methanol fuel (CH3OH) from the greenhouse gases CH4 and CO2 is developed, by making use of a novel, fully electrified plasma process. The complete setup includes a novel movable electrode stable atmospheric pressure glow discharge reactor (background and property of UAntwerpen), a methanol synthesis reactor, and a gas control system, aiming for optimal energy efficiency. The aim of the plasma process is the conversion of CH4 and CO2 into syngas, with optimal H2/CO ratio of 2, for methanol synthesis. This will be investigated in a broad range of applied power, gas flow rate and CH4/CO2 ratio, as well as by introduction of water vapor, to realize this optimal H2/CO ratio. The scientific work will be carried out at BlueApp, the innovative pre‐incubator for sustainable chemistry.

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Development of a plasma device for rapid disinfection of contaminated hospital materials: Hospital‐Use Plasma Unit (HUP‐Unit). 01/09/2022 - 31/08/2023

Abstract

The SARS‐CoV‐2 pandemic has exposed how unprepared our society was in preventing the propagation of highly infectious diseases, protecting the healthcare providers and patients, and efficiently organizing the logistics, while managing large numbers of patients. For the past two years, hospitals have battled to mitigate the spread of the virus in their facilities, a challenge that included the need to daily dispose of thousands of unused, individually‐packaged medical products that could not be disinfected with the traditional disinfection methods. On average, the Antwerp University Hospital (UZA) produced around 250,000 kg of medical waste per year. In 2021, the amounts of medical waste increased by more than 10% compared to the pre‐COVID period. Globally, the pandemic not only increased the cost for hospitals, but it also increased the generation of waste around the world by 400‐500%. Moreover, at the height of the pandemic, there was even a critical shortage of medical supplies. Therefore, this was not only an environmental and financial issue, but also a serious healthcare burden. In order to be better prepared for future pandemics, we have prepared a mission‐oriented innovation project, which responds to a specific request from the Intensive Care Unit (ICU) at UZA. In our IOF‐POC CREATE project here, we aim to develop a non‐thermal plasma (NTP)‐based disinfection device to rapidly eliminate viruses from unused, individually‐packaged medical products: the hospital‐use plasma unit (HUP‐unit). Our HUP‐device will utilize a completely innovative cylindrical geometry design feature with materials to be disinfected, to enhance NTP generation and contact with a large volume of material, and ensure complete, uniform treatment. Indeed, we have to design a completely novel NTP device concept, which we will categorize as a 'moving‐bed' dielectric barrier discharge (DBD). By using the individually‐packaged hospital products as part of the NTP generation mechanism, our 'moving‐bed' DBD HUP‐unit offers a scalable solution to provide rapid disinfection in the hospital. Based on our understanding of plasma dynamics and computational plasma simulations, we have developed this theoretical design, but the feasibility of creating a working prototype remains to be seen. Therefore, in this IOF‐POC CREATE project, we will produce and validate our prototype HUP‐unit in the lab. If successful, our HUP‐unit will allow us to: i) mitigate shortages in individually‐packaged medical products; ii) reduce the waste produced by healthcare facilities and associated waste management cost; iii) reduce the incidence of hospital‐acquired infections.

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Fixing Nitrogen and splitting Carbon dioxide on Mars using microwave plasma. 13/01/2022 - 12/01/2023

Abstract

The concept of plasma-based gas conversion on Mars is an intriguing prospect for in-situ resource utilisation (ISRU). O2 and CO mixtures could be efficiently produced by dissociating CO2 harvested from the Martian ambient for life support and fuel, respectively. In this study, we propose to interrogate a novel prototype solid-state microwave (MW) plasma reactor for in-situ gas conversion using Martian atmospheric gases and conditions. Along with CO2 conversion to O2 and CO, the feasibility of plasma-based nitrogen fixation (NF) will be explored for the first time, the key energy hurdle for in-situ fertiliser production. MW plasma-based conversion can lower the effective dissociation energy of breaking molecules such as CO2 (~96 % of Martian atmosphere) and N2 (~2 %) opening up efficient pathways not available via thermal kinetics. The extremely stable nitrogen triple bond (~9.8 eV), for instance, can be oxidised by O2 formed from the co-conversion of CO2 fraction of the Martian atmosphere. MW plasmas can operate over a wide range of power and pressure conditions with a high ionisation fraction and therefore high gas conversion level. This electrically driven approach can also be directly coupled to intermittent renewable electricity sources such as Martian harvested solar energy (i.e., no energy storage requirements due to the rapid start up time). Powered by recent advances in solid state technology, low mass and small footprint MW reactors which have superior control, efficiency and longevity compared to legacy magnetron devices, are now a possibility. Plasma-based MW gas conversion is therefore an exciting candidate for future ISRU focused missions to the red planet and beyond.

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Valorization of airborne ammonia emissions of livestock farming by plasma-enabled conversion to ammonium nitrate fertilizer. 01/01/2022 - 31/12/2023

Abstract

Ammonia emission by livestock farms in general and in the vicinity of Natura 2000 areas in particular is subject to increasingly stringent European and Flemish regulations. Meeting the eminent more stringent legislation will be technologically very challenging. Currently the best available technology for recovering the ammonia is by scrubbing the ventilated air with diluted sulphuric acid solution. Captured ammonia is converted to ammonium sulphate by reaction with sulphuric acid in the air washing device. Because of the limited solubility of ammonium sulphate, the obtained solution has little economic value as fertilizer, and large storage reservoirs are needed. We propose an innovative air scrubber concept with local production of nitric acid (HNO3) simply from oxygen, nitrogen and water molecules from air by a plasma reactor. In the scrubber ammonia reacts with nitric acid to ammonium nitrate, which is a superior fertilizer with larger economic value. The solubility of ammonium nitrate is much larger than for ammonium sulphate, which will minimize the volume of water and product to be handled. There will be no need for chemicals such as sulphuric acid. Reagents are locally produced simply from air by a plasma reactor. This original solution of an air pollution problem fits well with the notion of circularity since ammonia originating for the animal feed is converted to fertilizer for crop production.

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Research gifts for the group PLASMANT 01/01/2022 - 31/12/2023

Abstract

The research within the group PLASMANT focuses on studying plasmas by modeling and experiments, for two main applications, i.e., sustainable chemistry (CO2 conversion, CH4 conversion into olefins or for H2 production, N2 fixation for fertilizer applications, NH3 cracking for H2 production, dry reforming of methane for syngas of oxygenate production,...) and plasma medicine (mainly cancer treatment, but also virus inactivation).

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Award 'Robert Oppenheimer' - 2021. 01/12/2021 - 31/12/2022

Abstract

Non-thermal plasma (NTP) technology has been investigated for its anti-cancer and immunogenic effects for cancer therapy. NTP systems for biomedical applications have been thoroughly characterized for in vitro systems, which include component analysis (e.g. pulsed-electric fields, UV radiation), gas-phase measurements of excited and reactive species, and liquid chemistry studies. Already it has been shown to induce immunogenic cell death (ICD), a highly favorable type of cell death for cancer immunotherapy that is characterized by the release of 'danger signals', known to stimulate key immune cells for initiating an adaptive immune response. Despite promising advances in plasma therapy for cancers (a field now coined as 'plasma oncology'), several gaps in knowledge still remain which hinder translation of this technology including: 1) determining the proper 'NTP treatment dose' and 2) defining effective treatment schedules for combination therapies. In this study, we aim to correlate NTP treatment dose to anti-cancer effect and determine the efficacy of NTP treatment in strategic combination other therapies. To investigate this, an in vivo cancer model will be used in order take into account the complex interactions between NTP, the tumor, the tumor microenvironment, and the immune system. We will use the B16-F10 melanoma cell line with syngeneic C57BL/6J mice. Results of these experiments will provide insight into standardizing NTP treatment and help streamline adoption of NTP technologies into the clinic.

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Towards the accurate modelling of the "building blocks" of plasma catalysis. 01/08/2021 - 31/07/2023

Abstract

Plasma catalysis is a potential technology to convert sustainable energy into value-added chemicals. However, little is known about how plasma catalysis works. Therefore, fundamental "building blocks" of plasma catalysis will be investigated here, i.e., the effect of vibrational excitation, electric fields, and charged surfaces, as induced by plasma . To do so, several different methods will be developed and combined with neural network potentials (NNPs). Furthermore, with these tools, accurate dynamical studies will be performed for the first time, for molecule-metal surface reactions under plasma conditions for the first time. By performing dynamical atomistic studies, insight into plasma reaction mechanisms can be gained. Such dynamical insights will then subsequently be implemented into a newly developed microkinetic model, which goes beyond microkinetic models that traditionally operate from a static point of view. Specifically, the reaction of vibrationally excited methane on Pt(111) will be investigated and tested against experiments in order to validate the employed approach. Furthermore, the dissociation of CO2 on Cu(111) upon influence of an electric field and a charged surface will be investigated with the newly developed methods and a state-of-the-art NNP. Finally, a microkinetic model for the hydrogenation of CO2 towards methanol on Cu(111) will be developed, which will include the aforementioned dynamical effects .

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Power up sustainable production of chemicals by plasma catalysis (PLASMACAT). 01/07/2021 - 30/06/2022

Abstract

This project focuses on plasma catalysis, which is the combined use of a plasma source and a catalytic material, and it is a new research area in Denmark. To assist in a fast entry in this area, the project coordinator from Denmark wanted to set up this collaboration with me, as well as with Haldor Topsøe A/S, being one of the leading companies within catalysis today. The objective is to evaluate the potential of plasma catalysis in selected chemical synthesis processes with strategic relevance for a future where production of chemicals will change from a fossil fuel basis to a sustainable production, with the focus on oxidative activation of methane, which is thermodynamically favored at the lower temperatures where the advantages of non-thermal plasma will be exploited.

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CO2 utilization for the circular economy (D-CRBN). 01/04/2021 - 30/03/2022

Abstract

This postdoc project consists of two phases. The aim of phase 1 is to design innovative plasma reactors based on fundamental principles, and the knowledge present at PLASMANT. In the meantime, D-CRBN, the spin-off company of UAntwerp, targets a proof-of-principle of an improved atmospheric plasma reactor. In phase 2, the best reactor design will be constructed based on all collected information, and a complete prototype will be developed to be used by D-CRBN.

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Fertiliser from air by plasma treatment (Sustainable Manure). 01/12/2020 - 30/11/2022

Abstract

This project's main objective is the commercialisation of a breakthrough technology for upgrading livestock manure to an improved fertiliser. The overall aim of the project is to fundamentally improve global food production, by increasing productivity and reducing emissions. The technology enables farmers to produce environmentally friendly fertiliser on the farm using slurry or biogas digestate, air and electricity. The technology is a manure processing unit that consists of a plasma reactor, an absorption system and a plasma generator with power supply. The consortium consists of three organisations, ScanArc Plasma Technologies AS, University of Antwerp and N2 Applied. The plasma technology for treating livestock manure, is an innovative technology with the following benefits: • providing a cost-effective alternative to chemical fertiliser, and thus improving farm economics • ensuring compliance with stricter environmental regulations, which in turn mitigates risk for farmers and ensures business continuity • reducing emissions in the farm-cycle and thus contributing to reducing greenhouse gases and air pollution • removing odour, giving the farmer flexibility in spreading, optimising the fertilising effect of manure, which reduces nutrient loss and pollution.

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Plasma-catalytic hydrogenation of CO2 to CH3OH: Study of the underlying mechanisms by integrated microkinetic modeling of plasma chemistry and surface reactions. 01/11/2020 - 31/10/2024

Abstract

There is a growing interest into strategies to convert CO2 into high-value chemicals. An interesting route is hydrogenation to CH3OH, which is a valuable fuel and chemical intermediate. However, by heterogeneous catalysis, the CO2 conversion and the corresponding CH3OH selectivity are limited by thermodynamics. A possible solution is combining catalysis with non-thermal plasma, which offers a unique way to enable kinetically limited processes, while maintaining thermodynamically favourable temperatures. In my project, I will computationally study the plasma-catalytic conversion of CO2 to CH3OH to gain a better understanding of the underlying mechanisms. Indeed, the knowledge of the mechanisms governing plasma catalysis is quite limited. I will start by developing a 0D chemical kinetics model for a CO2/H2 plasma. Subsequently, I will develop a microkinetic surface model to simulate the reactions occurring at the catalyst surface. In the following step I will couple these models to gain insight in how the catalyst reactions affect the gas phase composition and vice versa. I will also investigate the effect of different catalyst materials and of ZnO promotion. These models will be validated with experiments and improved when they do not produce adequate results. The ultimate goal is to optimize the plasma and catalyst conditions for the plasma-catalytic hydrogenation of CO2 to CH3OH.

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Nitrogen fixation through plasma-liquid interaction: Computational and experimental studies. 01/11/2020 - 31/10/2024

Abstract

The NH3 produced in the Haber-Bosch (H-B) process today sustains over 40% of the global population in the form of fertilizer. However, the H-B process is an extremely energy-intensive and CO2 emitting process that does not have much room left for optimization. In light of the pressing issue of climate change, the world thus calls for an environmentally friendly alternative for nitrogen fixation. My project will explore plasma-liquid interaction as a possible alternative. Plasma-based NH3 synthesis in general has the advantage of working at ambient conditions and can be coupled to renewable energy. Plasma-liquid interaction provides an additional advantage of eliminating the CO2-emitting methane steam reforming step, as it uses H2O as the hydrogen source instead of H2. To be able to optimize NH3 synthesis through plasma-liquid interaction, an in-depth knowledge of the underlying mechanisms is needed, which I aim to obtain through a combined 0D-2D modeling approach. I will use two different plasma sources, i.e. jet and DBD, and investigate their advantages and how to optimize their NH3 production. A research stay is planned at MIPSE for the development of the DBD model. Finally, I will perform experiments for validation of the models, as well as to gain a more complete understanding of the plasma-liquid systems and their capabilities.

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Model-based reactor design improvement in a gliding arc plasmatron for CO2 conversion with and without catalyst. 01/11/2020 - 31/10/2024

Abstract

Global warming is a complex problem and the pressure for change is high. One pressing aspect is the greenhouse gas CO2. By converting the CO2 into value added chemicals and fuels, a sustainable cycle can be established. Plasma technology has the potential to fulfill this role, especially with the gliding arc plasmatron (GAP) reactor. However, its current performance is not sufficient. My project will focus on the conversion of CO2 and CO2/CH4 mixtures into value added chemicals in this reactor. Indeed, despite the promising results of the GAP, the current GAP design also faces limitations. Therefore, to optimize the conversion and energy efficiency, innovative designs are crucial. Moreover, the implementation of a catalyst for increased conversion and selectivity has not been tested. In order to achieve an optimal design and catalyst implementation, a thorough knowledge of the underlying mechanisms is needed, which I will gain by modeling and experiments. I plan to develop new designs by combining 0D chemical kinetics modeling and 3D fluid dynamics modeling, both with and without a catalytic bed. I will then validate these models experimentally. For dedicated plasma diagnostics, I will perform two research stays of two months each, i.e. at the Eindhoven University of Technology and Bochum University. In the end, this combined study will result in a fundamental understanding of this plasma reactor for an optimized performance.

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Computational exploration of new pathways in gas conversion on novel nanocatalysts. 01/11/2020 - 31/10/2024

Abstract

Conversion of greenhouse gases (especially CH4 and CO2) to valueadded chemicals is of great importance in the context of climate change as well as chemical industry. The traditional conversion of CH4 and CO2 often requires high temperature and pressure using expensive and polluting metal surfaces. Finding a clean catalyst with high selectivity to directly synthesize fuels from CH4 and CO2 gases at room temperature would thus be very beneficial from chemical, environmental and economic perspective. Recently, single individual metal atoms anchored to graphene-based materials are explored as novel materials not only because they minimize material usage, but also because they may surpass conventional catalysts in terms of the high specific activity. In this project, I will employ DFT calculations to explore a new class of nanocatalysts by tailoring their surfaces. The detailed mechanisms of direct chemical and electrochemical conversion of CH4 and CO2 gases to fuels on these tailored nanocatalysts will be studied. I will explore how these mechanisms control the reaction rates by developing a specific kinetic model for each chemical (electrochemical) reaction. To obtain a more global understanding of optimized conversion and energy efficiencies, the computational results will be compared to both experimental literature data and collaboration results.

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From physical plasma to cellular pathway: a multi-disciplinary approach to unravel the response pathways induced by nonthermal plasma for cancer therapy. 01/10/2020 - 30/09/2023

Abstract

Cancer therapy has been rapidly transforming in part due to progress in seemingly unrelated fields. This has led to the development of profound tools for studying cancer pathways and innovative therapies. Non-thermal plasma (NTP) is a novel treatment that has been emerging for cancer immunotherapy. Bioinformatics is another field experiencing rapid growth, as the ability to collect and process large amounts of 'omics' data has become increasingly accessible. In the context of oncology, this has led to success in elucidating therapy-induced pathways and therapy target discovery. Therefore, in my project, I will use a combination of experimental and bioinformatics approaches to study fundamental effects of NTP on cancerous cells: 1) mechanisms driving cell sensitivity and 2) immunological changes to be exploited for combination therapy. In vitro experiments will be performed to categorize cells into sensitivity groups based on NTP-induced cell death; cellular redox and death modalities will also be studied. Transcriptome analysis and bioinformatics techniques will be used to uncover the activated pathways. Signature gene sets from transcriptome data will be studied to obtain a more comprehensive picture of the immunologic changes in NTP-treated cells. All in silico results will be validated experimentally. Success of this project will benefit multiple science fields and open new lines of research while providing insight into underlying mechanisms of NTP-induced cancer response.

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Plasma-liquid interaction: Combined 0D-2D modeling and experimental validation. 01/01/2020 - 31/12/2023

Abstract

Plasma-liquid interaction is an important subfield of plasma science, with several promising applications, including water treatment, chemical synthesis, and especially in plasma medicine, e.g., cancer treatment, where plasma-treated liquids seem to have similar anti-cancer properties as the plasma itself, and can be more readily applied, e.g., to tumors inside the body. However, in spite of the growing interest in plasma-liquid interaction, there is still a poor understanding of the fundamental physical and chemical processes at the plasma-liquid interface and inside the liquid. The aim of this project is to obtain detailed insight in these mechanisms, by means of combined 0D-2D modeling, for two major plasma types, i.e., a plasma jet and a dielectric barrier discharge (DBD). The combination of 0D and 2D models is very interesting, because it allows us to combine their advantages, while avoiding their drawbacks. Indeed, a 0D model will describe the full plasma-liquid chemistry (i.e. gas phase, interface and liquid phase) with limited calculation time, but without spatial information, while the 2D fluid dynamics models will include limited chemistry, as they are time-consuming, but they will focus on the physical mechanisms of the interaction, including gas and liquid flow dynamics and transport of species, and DBD streamer interaction with the liquid. Finally, experiments will be performed to measure the important species in the liquid, in order to validate the models.

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Investigating fundamental plasma effects on tumor microenvironment through development of a controlled plasma treatment system for clinical cancer therapy. 01/01/2020 - 31/12/2023

Abstract

Non-thermal plasma technology is gaining attention as a novel cancer therapeutic. In the clinic, plasma has been applied to patients with head and neck squamous cell carcinoma, the 6th most common cancer worldwide with long-term survival below 50%. While initial studies are promising (e.g. partial remission, decreased levels of pain, no reported side-effects), a critical issue became apparent when translating plasma technology from the laboratory to the clinic: low reproducibility of treatment. Current plasma devices are handheld and require the operator (clinician) to make a judgement as to how long to treat the patient. This leads to large variability, which becomes even more pronounced when the clinician must move the plasma applicator over a large area of treatment. We aim to develop a robotic plasma treatment system that will enable us to investigate fundamental plasma effects on the tumor for clinical cancer therapy. We will use multiple sensors to detect the patient environment, artificial intelligence to 'learn and predict' patient disturbance patterns (e.g. breathing), and a robotic arm to deliver plasma. We will test our developed system in 3D and mouse cancer models and study the consequence of plasma treatment in the tumor, and to the survival of the animal. Altogether, our project will progress plasma technology for clinical translation by elucidating previously unknown biological responses to plasma and addressing issues in the clinic.

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Dioxide to monoxide (D2M): innovative catalysis for CO2 to CO conversion (D2M). 01/01/2020 - 30/09/2021

Abstract

The aim of this project is to study, explore and develop various (catalytic) technologies for the production of CO as platform chemical via conversion of CO2. A technology assessment will subsequently be carried out to evaluate the potential of each technology, pinpointing promising strategies for further development and upscaling. Concrete objectives and criteria The efficiency/productivity of existing homogeneous catalytic systems for CO2 reduction to CO will be mapped out and evaluated to identify the most promising systems to achieve this reduction and to explore ways to improve its larger scale viability through detailed catalyst modification studies. The focus will be on cobalt and nickel systems containing N-heterocyclic carbene (NHC) species as ligands. The goal of the heterogeneous catalytic conversion of CO2 to CO is to assess the potential of the oxidative propane dehydrogenation (OPD) reaction with CO2 as a soft oxidant. The main purpose here is to focus on and maximize CO2 reduction and CO formation via novel catalyst synthesis, surface engineering and investigation of catalyst support. In the field of electrocatalytic conversion of CO2 to CO we aim to (1) develop metal-based electrodes (electrocatalysts integrated in gas diffusion electrodes) exhibiting enhanced stability, (2) to investigate a novel type of metal-free electrocatalyst that can tackle the current challenges witnessed in N-doped carbons and (3) to demonstrate the continuous production of CO from CO2 by the development of a prototype lab scale reactor including the best-performing electrocatalysts developed in this project Another goal of this project is providing a proof-of-concept for plasmonic enhanced CO2 conversion into CO in an energy-lean process involving only solar light at ambient pressure as energy input i.e. without external heating. The objective of the plasma catalytic route for CO production is to enhance the conversion and energy efficiency of CO2 conversion in different plasma reactor types, with major focus on Gliding Arc plasma and Nanosecond pulsed discharges (NPD) plasma reactors. The project also takes up the challenge to activate CO2 and bio-CH4 and turn them into CO by combining chemical looping processes, into which catalysis is integrated, mediated by multifunctional materials (combine different functionalities into one smartly engineered material) and/or spatial organization of materials in dynamically operated packed-bed reactors.

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Power to chemicals (P2C). 01/01/2020 - 30/06/2021

Abstract

The aim of this project is to demonstrate CO2-neutral ammonia production by renewable electricity-driven processes via novel (photo-)electrocatalytic and plasma-based routes. Five scientific objectives have been defined. Objective 1. To reveal the mechanism of N2 activation in candidate electrocatalysts. The first step of the nitrogen reduction reaction (NRR), N2 activation that relies on the choice of electron donor-acceptor pairs, will be studied by means of density functional theory (DFT) calculations and mechanistic study of known transition metal compounds. Objective 2. To screen and rationally develop highly efficient electrocatalysts for NRR. Catalysts with the theoretically electron donor-acceptor pairs will be prepared, tested and further optimized to achieve efficient NRR. The aim is to develop low-cost and environmental-friendly electrocatalysts with a Faradaic efficiency over 10% at a current density of at least 0.1 mA/cm2. Objective 3. Investigation and optimization of extrinsic parameters for durable NRR performance. Mass transport limitations will be studied via electrocatalyst integration in tailor-made gas diffusion electrodes. The influence of process parameters will be investigated and optimized, aiming at electrode stability for continuous and stable NH3 production. Objective 4. Investigation and development of plasma reactors for NH3 production. Three different plasma setups will be investigated for NH3 production, i.e., dielectric barrier discharge (DBD) and gliding arc (GA), as well as a plasma jet interacting with liquid H2O. The first two setups will also be tested with the electrocatalysts. The experiments will be supported by modeling, and conditions with maximum NH3 yield and minimum energy cost will be explored. The target is to achieve an NH3 yield above 1% and energy cost below 30 MJ/mol. Objective 5. Develop stand-alone electro- and plasma reactor driven by a photovoltaic solar cell. Integration of both reactor concepts (based on electrocatalytic and plasma (catalytic) ammonia production) to a stand-alone device powered with sunlight and usage of atmospheric air as feedstock. In a so-called ammonia panel concept, the electrolyser and plasma gas-flow reactors will be integrated with a photovoltaic solar cell. The N2 and H2O in air are used as reactant for ammonia production. The aim for this prototype is to realize an ammonia production rate of 6.2 mol h-1 m-2.

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CO2-conversion in a microwave plasma in the presence of H2O: Study of the underlying mechanisms by computational and experimental methods. 01/11/2019 - 31/10/2023

Abstract

Climate change is a pressing issue; therefore, action must be taken now. An important part of the fight against climate change is mitigation and prevention of CO2 from entering the atmosphere. However, this is not enough. By combining the prevention of more CO2 emission with the conversion of the CO2 already present in the atmosphere into value added (industrial) products and fuels, a more sustainable cycle can be created. My project will focus on conversion of CO2 in presence of H2O (a hydrogen source, often found in exhausts and the atmosphere) into value added chemicals by means of microwave (MW) plasma. Indeed, in spite of the abundance of H2O, there exist no models yet for CO2/H2O mixtures in MW plasma. To optimize the conversion, a thorough knowledge of the underlying mechanisms is needed, which I will obtain by combined modelling and experiments. I will develop a 0D chemical kinetics model and a 2D fluid dynamics model. For the experimental part, I will perform two times two research stays: at UMONS and DIFFER. I will evaluate the effect of various plasma and reactor parameters by both modelling and experiments, to obtain a more global understanding for optimized conversion and energy efficiency.

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Atmospheric plasma as green solution for enhanced adhesion and functionalization (PlasmaSol). 01/11/2019 - 31/10/2022

Abstract

The general purpose of the project is to use non-thermal atmospheric plasma technology as an eco-friendly surface modification method to replace the currently used non-ecofriendly processes and/or to achieve surface properties which are not within reach with other conventional processes. Within the PlasmaSol project, this technology will be researched to (i) assure a good adhesion between various substrates and foils or coatings, (ii) provide wood plastic composites and textiles with an antimicrobial functionality, and (iii) increase the flame retardant properties of textiles. By obtaining fundamental knowledge on the plasma chemistry and physics, thanks to a comprehensive toolset of advanced characterization techniques, a valuable dataset of suitable precursors compatible with the treated substrates will be obtained, finding applications in fields that might even fall outside of the scope of this project. To get more fundamental insight of the plasma process, the experimental work will be complemented by theoretical modeling of both the plasma reactor and nozzle design, by means of fluid dynamics modeling of the gas flow and the plasma process. The simulations will be performed for the extreme range of conditions of the equipment in order to determine an operational window of the plasma deposition process. To summarize, this fundamental work will assist and simplify the optimization and future implementation (i.e. industrialization) of the plasma deposition process.

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Understanding the chemistry at the plasma–catalyst interface through atomistic modeling. 01/10/2019 - 30/09/2022

Abstract

Recently, plasma catalysis is gaining interest as an alternative to traditional thermo-catalytic techniques. Due to the non-equilibrium physical state of the plasma, with much energy stored in a limited number of degrees of freedom, specific chemical processes can be selectively stimulated or inhibited, and the location of the chemical equilibrium can be shifted. Various physical effects at the plasma–catalyst interface—such as vibrationally excited molecules, excess charges, and electric fields—are nonexistent under purely thermal conditions, and can dramatically change the chemistry at the catalyst surface. However, very little is known about this new frontier in surface science due to lack of dedicated experiments or detailed models. In this project, I will explore the unique physicochemical phenomena that arise at the plasma–catalyst interface. I will develop an integrated atomistic modeling approach based on advanced first principles simulation techniques, unravel the fundamental mechanisms of plasma-induced processes at the catalyst, and reveal how new chemical regimes can be accessed through several types of selective plasma–catalyst coupling. Indeed, the unconventional chemistry at the plasma–catalyst interface constitutes a new, unexplored discipline of catalysis. The fundamental insights from this project would hence greatly improve our understanding of the physical chemistry of surfaces and can aid the development of new efficient gas conversion technologies.

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Plasma efficient nitrogen fixation (Penfix). 01/10/2019 - 30/09/2021

Abstract

Industrial scale nitrogen fixation (NF) via the Haber-Bosch process dominates artificial fertilizer production and at present, enables yield enhancements which nourish over 40 % of the world population. Owing to the exceptional stability of molecular nitrogen's triple bond the Haber-Bosch process is an energy intensive chemical process which accounts for 1-2 % of the world's energy production, consumes 2-3 % of the global natural gas output and emits more than 300 million tonnes of CO2. In light of an increasing population (and fertilizer demand) coupled with an urgency to reduce CO2 emissions, efforts to find alternative technologies for NF that offer the potential of reduced energy usage while minimizing greenhouse gas emissions have accelerated. Electrically powered plasma processes are considered as a promising alternative for delocalized fertilizer production, based on renewable energy, and more specifically for NO production. To-date, however, plasma designs for NF have not exceeded Haber-Bosch efficiencies. Pulsed powered microwave (MW) generated plasma technology offers some promise in this regard. Pulsing of the discharge power enables strategies which direct energy to primarily heat electrons ('non-thermal' conditions) providing a far more efficient pathway to molecular bond breakage (and resulting NO production) than thermal effects. Indeed, reports on pulsed powered MW discharges have indicated an opportunity to tune electron energies to maximize molecular vibrational excitation, identified as an optimal route for energy efficiency in NO production. In a novel advance, plasma efficient nitrogen fixation 'PENFIX', proposes to interrogate 'pulsed' powered atmospheric microwave (MW) plasma for nitric oxide (NO) production using air. Novel reactor designs informed by validated modelling will be of particular focus. Diagnostic and modelling activities will elucidate the fundamental physics while addressing the challenges of future industrial scale deployment.

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Atomic scale modeling for plasma-enhanced cancer immunotherapy: targeting the signal inhibitory proteins. 01/10/2019 - 30/09/2020

Abstract

Biomedical applications of cold atmospheric plasma (CAP) are gaining increasing interest. In particular, CAP seems very promising for cancer immunotherapy. However, the underlying mechanisms need to be better understood. CAP generates a rich mixture of reactive oxygen and nitrogen species (RONS), which interact with living cells, inducing molecular level modifications to their components (e.g., proteins) upon oxidation. This will influence the intra- and/or intercellular signaling pathways, leading to various alterations in the cellular metabolism, which are stated to cause immunogenic cancer cell death. To better understand the effect of plasma on the process of cancer cell elimination by the immune system, a fundamental insight in the protein-protein interactions of cancer and immune cells, and in the effect of plasma-induced oxidation, is crucial. Complementary to experiments, computer simulations allow us to study the underlying processes with nanoscale precision. Thus, in this project, I aim to elucidate the mechanisms of immunogenic cell death induced by plasma-generated RONS, which leads to unmasking the cancer cells and to effectively eliminating them by immune cells. Specifically, I will perform a combination of different atomic scale simulations to study the interaction between proteins of immune cells and cancer cells, and the subsequent effect of plasma-induced oxidation on their binding affinity.

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Plasma catalysis for CO2 recycling and green chemistry (PIONEER). 01/01/2019 - 31/12/2022

Abstract

The main objective of this project is the formation of a new generation of experts in the subject of CO2 valorization using plasma-catalytic coupled processes.Plasma intensification of CO2 valorization processes, such as CO2 hydrogenation and dry reforming of methane, can greatly contribute to the stabilization of CO2 concentration in our atmosphere through the production of synthetic fuels that will be involved in overall zero or near zero emission cycles. This alternative utilization of yet C-based fuels will play an important role in our transition to a 100% renewable future. Chemical and thermochemical CO2 valorization processes are hindered by very slow reaction kinetics. Catalysts are often used but, most of the time, they either are not enough, or their utilization is not feasible under real operation conditions. The use of plasmas in combination with a well-designed catalyst can turn this sluggish CO2 valorization processes feasible. There is however a complete lack of knowledge about almost every aspect of this plasma-catalysis coupling. Research efforts are directed towards the understanding of CO2 plasmas, their interaction with solid catalytic surfaces, the formation of excited species and the fundamentals of the reaction mechanisms involved. Different plasmas and different catalysts are needed. Novel reactor concepts need to be found. The PhD topics cover many different scientific disciplines: from the physics of plasmas to the physicochemical characterization of solid surfaces and catalysis. The students will be instructed in several fields, not only considering science but also other important skills, such as soft skills training, as well as specific formation on managing, marketing and business skills along the duration of this project.

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Designing the packing materials and catalysts for selective and energy efficient plasma-driven conversion (PLASMACATDESIGN). 01/01/2019 - 31/12/2022

Abstract

PlasMaCatDESIGN aims to develop design rules for (catalytically activated) packing materials to enhance plasma-activated gas phase conversion reactions to basic chemicals. By understanding the material - properties – activity correlation we target enhanced conversion, selectivity and energy efficiency of plasma driven chemical production for two selected industrially and environmentally relevant model reactions in which plasma catalysis can have specific advantages: selective CO2 conversion towards C1-C5 (oxygenated) hydrocarbons and inorganic amine synthesis (nitrogen fixation).

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Atomic thin membranes for water and ion transport. 01/01/2019 - 31/12/2022

Abstract

Membranes are used for different separation processes with applications in areas as diverse as water desalination, gas separation, energy technologies, microfluidics and medicine. Due to its atomic thickness and its exceptional mechanical properties, graphene and related materials have opened up new possibilities in membrane technologies. Such membranes will be investigated for water and hydrogen transport, ion sieving and hydrogen isotope separation. Fundamental insights into mass transport at the nanoscale will be obtained through theoretical and computational modelling with intensive collaboration with experimentalists for validation.

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Plasma-based cancer treatment: Atomic level simulations. 01/10/2018 - 30/09/2021

Abstract

Cold atmospheric plasmas (CAPs) have attracted significant interest for their promising applications, particularly in cancer therapy. Understanding the anticancer activity of CAP treatment, however, still remains a key challenge. It is largely accepted that the biological effects of CAP are attributed to reactive oxygen and nitrogen species (RONS). It is suggested that CAP-generated RONS regulate key biochemical pathways within intra- and intercellular environments, inducing chemical and physical changes in cells. Yet, the underlying mechanisms are not fully understood. In this project, we aim to gain a better insight into the mechanisms of the effect of CAP on cancer cells, using atomistic simulations to investigate the interaction mechanisms of RONS with 6 different proteins, which play a vital role in cancer (treatment). We use reactive and non-reactive molecular dynamics simulations to study the CAP-induced structural and functional changes in antioxidant, transmembrane and cell-surface proteins, as well as the subsequent effects on their protecting, transporting and binding properties, which will eventually result in cancer cell death.

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Multiscale numerical simulations of magnetron sputter deposition. 01/10/2018 - 31/03/2019

Abstract

Numerical simulations allow to gain insight in basic processes underlying the complexity of real-life experiments. In this project, multiscale simulations are carried out to investigate the formation of thin catalytic Pt layers in a magnetron sputter deposition setup. Fluid simulations are employed to study the macroscale sputter deposition process. This provides the input needed for the subsequent microscale / atomic scale simulations. In these atomic scale simulations, novel methodologies – in particular collective variable-driven hyperdynamics – are used to access time scales well beyond the reach of standard molecular dynamics techniques. From these simulations, we hope to reach a better understanding of how the morphology and structure of thin Pt films is formed and could be steered.

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Plasma-treated liquids for cancer treatment: elucidating the selectivity against cancer cells by a combined experimental and computational study. 01/10/2018 - 31/01/2019

Abstract

Cold atmospheric plasma (CAP) is gaining interest for cancer treatment, although the application is still in its early stages. Besides direct CAP treatment of cancer cells, plasma can also be used to treat liquids, which appear to have similar anti-cancer effects as the plasma itself. These plasmatreated liquids (PTL) are very promising for cancer treatment, as they can be more generally used, e.g. they might be directly injected into tissue of patients. However, the selectivity of PTL treatment towards cancer cells, leaving normal cells undamaged, is only scarcely explored. This is exactly the focus of this project. We will try to define which cancer cell types are more (or less) sensitive towards PTL treatment and how selectivity towards cancer cells can be promoted. For this purpose, we will link the chemical composition of the PTL (reactive oxygen, nitrogen and chlorine species) with the selectivity in cancer vs. normal cell cytotoxicity, to know which species promote this selectivity (WP1). In parallel, we will develop a 0D and 2D computational model to simulate the plasma-liquid interactions (WP2+3). With the knowledge obtained in WP1, we can use the models to elucidate which plasma treatment conditions enhance the selectivity. Then, we will apply these conditions in the patient cell experiments to optimize the selectivity (WP4). Finally, we will also strive to unravel the underlying mechanisms of this selectivity in the cell experiments (WP4).

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Experimental and theoretical study of the fundamental mechanisms of nitrogen fixation by plasma and plasma-catalysis: towards the development of novel, environmentally friendly and efficient processes (NITROPLASM). 01/01/2018 - 31/12/2021

Abstract

Nitrogen is a crucial element for living organisms on earth. Transforming atmospheric N2 into molecules that can be incorporated by most organisms (N2 fixation) is either done by microorganisms or through energetically costly chemical processes (lightning strikes, Haber- Bosch (H-B) process). As the theoretical limit for the energy consumption of N2 fixation via non-thermal plasma (NTP) is more than 2.5 times lower than the energy consumption of the H-B process, this project aims to exploit NTP processes to fix N2 by reduction and by oxidation. The objective is to acquire an in depth understanding of the N2 fixation mechanisms in N2/O2 and N2/CH4 plasmas by combining experimental and numerical investigations of a wide range of gas and plasma-liquid discharges. To increase the N2 fixation rate and the yield, plasma catalysis will also be studied in the same gas mixtures. Catalysts will be prepared traditionally but also by plasma-based calcination and plasma-based modification of supports and synthesized catalysts. By successfully completing this project, we will gain fundamental understanding of the mechanisms and master plasma assisted N2 fixation in the gas phase, liquid phase and on catalyst surfaces.

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Plasma catalysis at the nanoscale: A generic Monte Carlo model for the investigation of the diffusion and the chemical reactions of plasma species at porous catalysts. 01/10/2017 - 30/09/2020

Abstract

In this project we will develop a generic model to simulate the diffusion of plasma species in and out of the pores of a catalyst and the catalytic reactions at the pore surface. In this way we will try to gather insight in the underlying processes in plasma catalysis in general and in the plasma catalytic conversion of CO2 and H2 to methanol specifically. In this project, we will focus on the conversion on a Cu-catalyst. Using quantum chemical calculations we will determine the properties of adsorption of the most important plasma species and the different reaction mechanisms and reaction rates at the surface. In parallel we will develop a Monte Carlo model to examine the diffusion of plasma species inside catalyst pores, as well as their surface reactions, for which we will make use of the results provided by the quantum chemical calculations. This model will allow us to investigate the role of plasma species in the methanol synthesis, the influence of the pore size and the pore shape on the total yield, which reaction products and side products are formed and whether these products can diffuse out of the pores to make room for new reactants. The results of this study will provide the necessary information for understanding plasma catalytic processes at a fundamental level and are essential to further optimise these promising processes.

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Modelling and experimental validation of a flowing atmospheric pressure afterglow source used for ambient ionization mass spectrometry. 01/10/2017 - 30/09/2020

Abstract

Ambient desorption/ionization mass spectrometry is a new field of mass spectrometry, which is becoming increasingly popular in analytical chemistry. An ion source that is gaining increasing interest for this purpose is the flowing atmospheric pressure afterglow (FAPA). It has two separated regions: the plasma ignition zone and the afterglow, which is generated outside the chamber and where the analytes are introduced. Hence, it allows the analysis of samples in the open, ambient environment. The ions and metastables from the plasma react with air constituents, resulting in the formation of reagent ions, which are then capable of ionizing the analyte of interest. The ions of the analyte material are finally detected by a mass spectrometer. The aim of my project is to identify the main ionization mechanisms in the reagent ion formation. First I will develop a zero-dimensional (0D) chemical kinetics model to describe the plasma chemistry of a helium plasma with air impurities, flowing into humid air, and the formation of reagent and analyte ions. Subsequently I will insert the obtained (and reduced) chemistry set into a 2D fluid model to describe the gas flow dynamics as well as the chemistry of the active plasma region and flowing afterglow, and I will study in detail the ionization pathways for a wide range of conditions. I will validate the model with experiments performed during two research visits at Rensselaer Polytechnic Institute (US).

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Long time scale dynamics of carbon nanostructure growth 01/10/2017 - 30/09/2020

Abstract

The spectacular properties of carbon nanotubes and graphene have generated worldwide commercial interest in these materials. However, realizing their full application in nanotechnology requires fundamental knowledge which is currently lacking. In particular, their properties strongly depend on their exact structure. How to control the structure during the growth is still elusive. Plasma-enhanced chemical vapor deposition (PECVD) has been envisaged as a means towards structure control due its ability to narrow the resulting chirality distribution with respect to thermal CVD and other growth techniques. In PECVD, however, several synergistic effects, such as the interplay between growth species, electric field and catalyst have not been investigated yet. Also, simultaneous etching complicates the PECVD-based growth process of CNTs and graphene considerably. Moreover, also the nucleation mechanism of multi-walled CNTs in both CVD setups is still unclear. In this project, we aim to study both CVD-based growth processes in the picosecond-to-seconds regime, by making use of a novel, in-house developed simulation method, called collective variable-driven hyperdynamics. In particular, we will analyze the intermediate nanoscale mechanisms in detail, focussing explicitly on the synergistic effects, which are extremely difficult to observe directly by experiments. We envisage that this research will lead to the understanding that is required to eventually control the carbon structure.

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Elucidating mechanisms of plasma-induced immunogenic cancer cell death and determining efficacy to elicit anti-tumor immunity: An experimental and computational study 01/10/2017 - 30/09/2020

Abstract

Cancer is still a major healthcare issue and many conventional therapies overlook the role of the immune system in the resolution of this disease. Non-equilibrium plasma is emerging as a novel cancer treatment. Promising results showed that plasma can kill cancerous cells and stimulate immune cells, but experiments have largely been in vitro. To address this, we will perform in vivo mouse experiments to validate therapeutic efficacy of plasma and assess immune responses required to eliminate cancer. While treatment may be efficacious, the underlying mechanisms of plasma cancer therapy are not fully understood. When plasma is generated, a complex environment of electric fields, ultraviolet light, charged particles and neutral species is produced. To date, it is unclear which plasma components and reactive species play the major role in cancer therapy. Therefore, we will also delineate the components of plasma that elicit anti-cancer responses. In addition, we will develop a computational model that will predict the behavior of plasma-generated species in liquid, as cells and tissue are treated in the presence of liquid. This will be compared to chemical analysis of plasma-treated liquid for validation and establishment of crucial species for cancer therapy. Altogether, this project will support development of plasma technology for cancer immunotherapy and provide insight into the underlying mechanisms.

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Modelling a gliding arc plasma reactor by means of COMSOL Multiphysics 01/10/2017 - 30/09/2019

Abstract

The beginning of the 21st century is marked by the rising awareness of global warming. The greenhouse gases CO2 and CH4 emitted in the atmosphere by industrial processes and the transportation sector are of major concern. Several efforts are being reported for greenhouse gas reduction by means of process optimization and application of new technologies. A new, promising method is the conversion of these greenhouse gases into value-added chemicals by means of atmospheric pressure plasmas, because of their reliability, efficiency, and ease of use. One of the most promising types is the Gliding Arc discharge (GA). GA plasma sources are favored for their high conversion efficiency and simplicity. They are non-thermal plasma sources, able to produce a high plasma density at a relatively low gas temperature (<3000K). Recently, a new type of GA plasma source, based on the innovative reverse-vortex gas flow stabilization, has been developed, allowing for even higher conversion efficiency and lower electrode degradation. However, this type of GA has not yet been studied in detail. The aim of this project is to gain fundamental knowledge on the physical processes inside the reverse-vortex stabilized GA by means of extensive computer modeling based on the COMSOL Multiphysics Software. Initially, 1D and 2D fluid plasma models will be developed, with later extension into a 3D model. The complete 3D model will involve the plasma physics and chemistry, fluid dynamics and heat transfer.

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Atomic scale simulations for a better understanding of cancer treatment by plasmas. 01/10/2017 - 30/09/2019

Abstract

Atmospheric pressure plasmas are gaining increasing interest for biomedical applications, like sterilization, wound treatment, dental treatment, blood coagulation, and especially cancer treatment. In the latter case, plasmas have demonstrated to give very promising results, both in vitro and in vivo, and are able to attack a wide range of cancer cell lines without damaging healthy cells. However, the underlying mechanisms are not yet fully understood. I will therefore perform atomic scale simulations to study the interaction mechanisms of reactive oxygen and nitrogen species (ROS, RNS) formed in the plasma with biomolecules, present in eukaryotic cells, which play a role in cancer (treatment). More specifically, I will apply classical molecular dynamics and density functional based tight binding simulations, and I will study three types of biomolecules, which play a crucial role in cancer (treatment): (1) a phospholipid bilayer (PLB) as model system for the cell membrane, (2) a part of a DNA string and (3) peptides, as a model system for proteins. I will investigate how the ROS and RNS interact with these biomolecules, which reaction products are formed, and how this can lead to apoptosis (cell death). This research will contribute to a better understanding of the role of plasmas in cancer treatment.

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Towards a fundamental understanding of electrical discharges in and in contact with water. 01/10/2017 - 30/09/2018

Abstract

Electrical discharges in contact with water are under intensive investigation for many possible and established implementations in environmental, chemical and biomedical applications. The fundamental mechanisms of plasma-water interaction are, however, still poorly understood. For instance, the initiation mechanism of electrical discharges directly into the water phase is a topic under debate. Next to that, there is no generally accepted theory on the self-sustainment mechanism of a dielectric barrier discharge (DBD) in contact with a water cathode. For that reason, this project is intended to obtain more fundamental insight in the underlying mechanisms of both plasma initiation in water and DBD in contact with water, by means of extensive modeling, validated by experiments. First, I will study the plasma-induced gas phase and water phase chemistry of both systems by means of 0D kinetics models. Next, I will include the 0D models into 1D and 2D COMSOL models for a more comprehensive simulation of the temporal and spatial plasma evolution. I will experimentally validate these models by means of various plasma diagnostic methods. Additionally, I aim to reveal new information on the investigated mechanisms with the experiments alone, by investigating the effect of the liquid content and voltage characteristics.

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Anticancer activity of plasma activated medium and its underlying mechanisms: Combined experimental and computational study (Anticancer-PAM). 01/09/2017 - 31/08/2019

Abstract

Cold atmospheric plasma (CAP) is gaining increasing interest for cancer treatment, although the application is still in its early stages. Besides direct CAP treatment of cancer cells, plasma can also be used to activate a liquid medium, which seems to have similar anti-cancer effects as the plasma itself. This so-called plasma activated medium (PAM) is very promising for cancer treatment, as it can be more generally used, e.g., it might be directly injected into tissue of patients. However, the anticancer potential of PAM is not yet fully understood. This is exactly the focus of this project. We will measure the reactive oxygen and nitrogen species (RONS) concentrations in PAM, and also calculate them with a model for plasma-liquid interaction. In addition, we will study the effect of PAM on a catalase model protein by experiments, and perform atomic scale simulations for the interaction of RONS with this protein, to better understand the effect of PAM on cancer cells, because catalase aids cancer cells in overcoming oxidative stress created by PAM.

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Low Temperature Plasma for applications in Medicine (LTPAM). 01/05/2017 - 30/04/2019

Abstract

Atmospheric pressure low temperature plasma (LTP) is a burgeoning field due to its vast potential in biomedical applications. Reacting with ambient air, these plasmas generate a variety of molecular, ionic and radical species, responsible for the anti-bacterial, anti-viral and anti-cancer properties ofLTP. It is especially important when more traditional therapies fail, such as antibiotic-resistant bacteria. Recently, a large number of studies of the biological effects ofLTP emerged, as well as diagnostics of the gas phase LTP, and various models. However, the chemical and physical processes in biologically relevant media still lack detailed understanding. Water is an essential part of the bio-milieu, and both initial and secondary LTP-induced chemistries in liquids require deeper studies. This project will aim at several goals, which will aid the progression ofLTP towards wide and diverse clinical use. 1) It will utilise the RF COST plasma jet (created to standardise the LTP research in Europe and the world). The sources of the reactive species induced by the jet will be studied by employing isotopically labelled molecules. 2) The plasma-induced chemistry will be studied in conditions mimicking those in vivo: (i) generation of secondary species from Cl-, one of the most abundant chemicals in bio-media, and assessment of their cytotoxicity; and (ii) quantitative identification of short-lived reactive species (radicals) created by LTP in gels, structures resembling tissue (this is especially important in the case of direct plasma exposure where radical chemistry greatly influences processes in liquids). 3) The enhancement of LTP effects will be studied via generation of ONOO- from its precursors in plasmas with aerosols. The work will be focussed on liquids' analysis by electron paramagnetic resonance and nuclear magnetic resonance spectroscopy, mass spectrometry, ion chromatography, etc.

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Towards plasma for cancer treatment: investigation of alterations in the DNA damage response due to plasma treatment in glioblastoma multiforme as tumour model. 01/01/2017 - 17/09/2017

Abstract

Recently, a new approach based on non-thermal plasma (NTP) to treat cancer cells is gaining interest in the medical field. Plasma is an ionized gas. It is a highly reactive mixture, containing electrons, ions, radicals and energetic neutrals, while still operating at room temperature. Precisely this combination of reactive species and low gas temperature makes it suitable for treating biological samples. It is suggested that the killing capacity of plasma is related to the formation of reactive oxygen and nitrogen species (RONS). Moreover, previous research showed that plasma can selectively kill cancer cells over healthy cells, which is an advantage over traditional treatment methods, such as radio- and chemotherapy. Unfortunately, little is known about the actual working mechanism, or selectivity, making it difficult to convince pharmaceutical collaborators to invest in this technique and develop it into a valuable treatment option for cancer. During this research, I will investigate the anti-cancer capacity of NTP, which RONS are responsible, and how NTP alters the DNA damage response (DDR) of cancer cells. The latter is a collection of mechanisms that are activated whenever DNA damage is detected in order to repair it. This is interesting because (a) plasma is shown to induce DNA damage, and (b) it is known that the DDR of cancer cells is already partially compromised, making it a valuable oncological target. I will use a brain tumour, glioblastoma multiforme, as model.

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Computational design of improved catalysts for plasma catalytic dry reforming of methane. 01/10/2016 - 30/09/2020

Abstract

This projects aims at the computational screening and design of bimetallic nanocatalysts for plasma catalytic dry reforming of methane. This reaction is highly interesting from both from an ecological as well as an economical point of view, since the reactants (CH4 and CO2) are strong greenhouse gases, while the product (syngas, i.e., a mixture of CO and H2) is the raw material for a wide variety of chemicals, including synthetic fuels. Based on extensive density functional theory calculations, a large number of potentially interesting catalyst candidates will be screened on 3 criteria: 1) adsorption and desorption of relevant plasma species from the catalyst surface (thermodynamic screening); 2) energy barriers of elementary reactions at the catalyst surface (1st kinetic screening); and 3) reaction rate coefficients of elementary reactions at the catalyst surface (2nd kinetic screening). In each of these steps, less suitable catalyst candidates are excluded in order to narrow down the list of remaining potentially interesting catalyst candidates. This will eventually lead to a list of catalysts which are theoretically suitable for syngas formation starting from plasma species derived from CH4 and CO2.

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Towards a fundamental understanding of plasma for cancer treatment: A combined experimental and computational study. 01/10/2016 - 30/09/2019

Abstract

Non-thermal plasma is gaining interest in recent years for cancer treatment. The underlying mechanisms are, however, not fully understood. Therefore, in this project we will study the interaction of plasma with cancer cells in vitro, and also perform computer simulations. The experiments will be carried out with a plasma jet, operating in helium with some oxygen and/or nitrogen, at different conditions. The plasma is created between two electrodes, but due to the gas flow, it is blown out of the discharge region and can reach the cancer cells to be treated, located at a distance of several mm. After plasma treatment, we will analyze the cell viability, cell morphology and change in cellular membrane integrity, as well as the expression levels of apoptosis related genes. In parallel we will perform computer simulations at two different levels. First, we will study the plasma chemistry at the different conditions used experimentally, by zero-dimensional reaction kinetics modeling, to reveal the most important (biochemically active) plasma species formed in each case. Second, we will apply united-atom non-reactive molecular dynamics simulations to study the important mechanism of phosphatidylserine flipflop in the cell membrane, known as signal for apoptosis (i.e., programmed cell death) of cancer cells. These simulations will give a better insight in the underlying mechanisms of plasma for cancer treatment, and will thus support the experimental work.

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Multi-timescale atomistic modeling of plasma catalysis and plasmabased growth of carbon nanostructures. 01/10/2016 - 30/09/2018

Abstract

In this project I will develop a novel atomic scale simulation tool to unravel the fundamental mechanisms underpinning complex plasma-based processes. Specifically, I will concentrate on plasma catalysis, which is envisaged to provide an energy efficient route for greenhouse gas conversion into value-added chemicals, and plasma-based growth of carbon nanostructures, which holds promise to offer control on structure and composition, unattainable by thermal methods.

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Plasma catalysis at the nanoscale: Model development for diffusion of plasma particles in pores and study of the catalytic behaviour at the pore surface. 01/10/2016 - 30/09/2017

Abstract

In this project we will develop a generic model to simulate the diffusion of plasma species in and out of catalyst pores and the catalytic reactions at the pore surface. We will try to gather insight in the underlying processes of plasma catalysis in general and of the plasma catalytic conversion of CO2 and H2 to methanol specifically. We will focus on the conversion on a Cu-catalyst. Using quantum chemical calculations we will determine the properties of adsorption of the most important plasma species and the different reaction mechanisms and reaction rates. In parallel we will develop a Monte Carlo model to examine the diffusion of plasma species inside catalyst pores, as well as their surface reactions, for which I will apply the results arising from the quantum chemical calculations. We will determine the minimum pore diameter needed for the plasma species to be able to penetrate the catalyst pores and undergo chemical reactions, which reaction products and side products are formed and whether these products can diffuse out of the pores to make room for new reactants. The results of this study will provide the necessary information to understand plasma catalytic processes at a fundamental level and are essential to further optimize these promising processes.

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Modeling of a microwave plasma reactor for energy-efficient CO2 conversion. 15/07/2016 - 14/07/2017

Abstract

In recent years, there is growing interest for plasma-based CO2 conversion, because it can proceed at mild reaction conditions, with limited energy consumption. The most promising plasma reactor, which has demonstrated the highest energy efficiencies up to now, is a microwave plasma reactor. The highest energy efficiencies reported up to now, however, are obtained at specific conditions, i.e., reduced gas pressure and supersonic gas flow, or special vortex gas flow. In this project, we want to investigate the underlying mechanisms of energy-efficient CO2 conversion in a plasma reactor, and to elucidate under which conditions the optimum conversion and energy efficiency can be obtained. This is preferably at atmospheric pressure, which is most convenient for later industrial implementation. For this purpose, we develop a model for a microwave plasma reactor, and the model results will be validated by comparison with experiments performed at collaborating research groups. The model development is done step-by-step, starting with a 0D chemical kinetics model to describe the CO2 plasma chemistry. The detailed plasma chemistry model needs to be reduced in order to be compatible with 2D and 3D models. In parallel, a 2D model for a microwave plasma in argon in a simple geometry is developed, and the reduced CO2 chemistry set will be incorporated in this 2D model. Subsequently, the 2D model will be extended to 3D, to allow studying microwave plasma reactors with supersonic gas flow and vortex gas flow. These models, after validation with experiments, will allow to investigate the most suitable conditions (gas pressure, applied power, frequency, reactor geometry, gas flow pattern and gas flow rate) for optimum CO2 conversion and energy efficiency.

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Computer modelling and experimental validation of plasmas and plasma- surface interactions, for a deep insight in cryogenic etching (Cryoetch). 08/06/2016 - 07/06/2018

Abstract

Microchips have caused a revolution in electronics over the last few decades. Following Moore's law, much effort has been put into continuously shrinking electronic feature dimensions. Indeed, typical feature sizes of semi-conductors decreased from 10 μm in 1971 to 14 nm in 2014. With the shrinkage of feature sizes, plasma etching plays a more and more important role due to its anisotropy during surface processing. However, to go beyond 14 nm features, current state-of-the-art plasma processing faces significant challenges, such as plasma induced damage. Recently, one such novel process with limited plasma damage is cryogenic etching of low-k material with SF6/O2/SiF4 and CxFy plasmas. In this project, the fundamental mechanisms of the plasma, and its interaction with the surface, for these gas mixtures, will be studied to improve cryogenic plasma etching. For this purpose, numerical models (a hybrid Monte Carlo - fluid model and molecular dynamics model) will be employed to describe (i) the plasma behavior for SF6/O2/SiF4 and CxFy gas mixtures applied for cryogenic etching, and (ii) the surface interactions of the plasma species with the substrate during etching. Furthermore, cryogenic etch experiments will also be conducted to validate the modeling results.

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Multi-scale modeling of plasma catalysis/ 01/01/2016 - 31/12/2019

Abstract

This project aims to obtain more insight in the fundamental processes of plasma catalysis by multi-scale modeling. The plasma chemistry in a CH4/CO2 mixture will be described by a 0D model, and inserted in a 3D macro-scale model of a packed bed reactor. The plasma behavior near/in catalyst pores will be modelled on a micro-scale. Finally, the plasma-catalyst interactions on the atomic scale will be modeled by classical MD and DFT simulations.

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Modeling and experimental validation of a gliding arc discharge: Comparison of a classical and a plasmatron gliding arc. 01/01/2016 - 31/12/2019

Abstract

The conversion of greenhouse gases (mainly CO2 and CH4) into value-added chemicals or renewable fuels is gaining increasing interest, to reduce the greenhouse gas concentrations and thus to solve the problem of global warming. A gliding arc plasma is very promising in this respect, as it can activate inert gas molecules at atmospheric pressure and moderate temperature with limited energy cost. However, the underlying mechanisms of a gliding arc are far from understood. In this project, we will try to obtain a better insight in the basic mechanisms of two types of gliding arc plasmas, i.e., a classical gliding arc, and a new type of reverse vortex flow gliding arc (plasmatron), which might be even more promising for greenhouse gas conversion. We will do this by means of extensive modeling, validated by experiments. First, we will study the plasma chemistry of a CH4/CO2 mixture. This plasma chemistry will be inserted in a coupled magnetohydrodynamics (MHD) - kinetics model to study the spatial and temporal plasma properties. The model will be validated by experiments, performed in Antwerp and in Liverpool. We will investigate the effects of CH4/CO2 ratio, discharge power and gas flow rates in both types of gliding arcs, on the gas conversion, the yields and selectivities of the formed products and on the energy efficiency, both theoretically and experimentally. This will allow us to predict which are the optimum conditions and plasma setup for the greenhouse gas conversion.

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Computational catalyst screening for chirality-controlled growth of carbon nanotubes 01/01/2016 - 31/12/2019

Abstract

Carbon nanotubes find many application in diverse areas, such as fibers in composite materials, as sensors, actuators, transistor components, etc. The electronic and optical properties of CNTs, however, are strongly dependent on the CNT chirality, i.e., on the exact CNT structure. This chirality is determined during the growth process, and hence it is very important to be able to control the growth process. The first goal of this project is therefore to unravel the CNT growth mechanisms and to understand the influence of the catalyst on the resulting chirality, by means of density functional theory (DFT) calculations. Experiments have shown that bi- and multi-metallic catalysts show great potential for chirality-specific growth. A generic screening procedure, capable to select possible suitable catalyst materials fast and cheap, would be highly beneficial. The development of such a procedure is therefore the second goal of this project. The screening procedure will consist of 1 thermodynamic and 2 kinetic screenings. DFT calculations will be performed for various bimetallic catalysts. CNTs with various charities will be modeled, as well as a number of CNTs with defects. The combination of these screenings will lead to two final goals: a correct reproduction of chirality-controlled growth for a known class of bimetallic catalysts, and the prediction of possible chirality-controlled growth for as yet unknown combinations of catalysts, which can be verified experimentally in collaboration with Tohoku University (Japan).

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Formation of hydroxyapatite coatings with tailored properties using radio-frequency mognetron sputtering through combined experiments and simulations. 01/12/2015 - 31/05/2016

Abstract

Ceramics based on hydroxyapatite is one of the most widely used materials for bone replacement, because of its high biocompatibility. Nowadays, HA-based coatings are commonly used in medicine to enhance the osteoinductive properties of metallic implants. In contrast to the relatively large number of experimental data, which in some cases can provide a global insight into the growth mechanism and structure of thin firms, there are currently very few atomistic studies using computer modeling to study the evolution of the coating structure and composition during thin film growth at the atomic level. Simulation of the HA coating growth process with desired properties deposited by RF-magnetron sputtering allows to gain insight in preparing the coating with tailored properties. Through detailed comparison between experimental and theoretical results, this project aims to further develop the scientific research, the mathematical model will help us to explicitly determine the physical and chemical phenomena that occur during the reactive deposition of the thin film, and will eventually allow to increase the resource efficiency of the industrial ion-plasma system.

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Atomic scale modeling for plasma cancer treatment. 01/10/2015 - 30/09/2018

Abstract

The application of cold atmospheric plasmas (CAPs) in medicine is increasingly gaining attention in recent years and is becoming one of the main topical areas of plasma research. The effective use of CAPs, however, is strongly dependent on the understanding of the underlying processes, both in the plasma and more importantly in the contact region of plasma with the living cells. In order to accurately control the processes occurring at the surface of the bio-organisms, there is a strong need to deeply investigate the exact interaction mechanisms of the plasma-generated species with biochemically relevant structures. This still remains a big challenge. Computer simulations may provide fundamental atomic level insight into the processes occurring at the surface of living cells, which is difficult or even impossible to obtain through experiments. Thus, in this project, I envisage to use atomistic simulations to investigate the interaction mechanisms of reactive plasma species with biomolecules, which play a crucial role in cancer (treatment), to better understand the underlying mechanisms of plasma oncology. For this purpose I will use reactive molecular dynamics as well as density functional based tight binding simulations. Specifically, I aim to determine whether plasma-induced reactive species can react and modify the biomolecular structure (or conformation) and change its function, which can eventually lead to cancer cell death (i.e., apoptosis).

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Computer modeling of plasmas and their surface processes, with experimental validation, for a better understanding of cryogenic etching. 01/10/2015 - 31/08/2018

Abstract

Plasmas are widely used in the microelectronics industry for the fabrication of computer chips, during plasma etching and deposition of materials. Following Moore's law, much effort is put into continuously decreasing electronic feature dimensions. Indeed, typical feature sizes decreased from 10 μm in 1971 to 14 nm in 2014. The gradual shrinking of features thus entails a continuous improvement of the plasma processes. To go beyond 14 nm features, it is crucial to limit plasma induced damage during processing. Recently, one such novel process to limit plasma damage is cryogenic etching of low-k material with SF6/O2/SiF4 and CxFy plasmas. In this project, I wish to obtain a fundamental understanding of the plasma behavior and its interaction with the surface, for these gas mixtures, to improve cryogenic plasma etching. For this purpose, I will apply numerical models to describe (i) the plasma behavior for SF6/O2/SiF4 and CxFy gas mixtures, and (ii) the surface interactions of the plasma species with the substrate. The plasma behavior will be simulated by a hybrid Monte Carlo - fluid model for addressing the various plasma species (electrons, ions, neutrals and excited species). The interaction of the plasma species with the substrate surface will be described by additional Monte Carlo and molecular dynamics (MD) simulations, allowing a detailed insight in the microscopic trench etching process. Furthermore, I plan to validate the models by means of cryogenic etch experiments.

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Modelling a gliding arc plasma reactor by means of COMSOL Multiphysics. 01/10/2015 - 30/09/2017

Abstract

The beginning of the 21st century is marked by the rising awareness of global warming. The greenhouse gases CO2 and CH4 emitted in the atmosphere by industrial processes and the transportation sector are of major concern. Several efforts are being reported for greenhouse gas reduction by means of process optimization and application of new technologies. A new, promising method is the conversion of these greenhouse gases into value-added chemicals by means of atmospheric pressure plasmas, because of their reliability, efficiency, and ease of use. One of the most promising types is the Gliding Arc discharge (GA). GA plasma sources are favored for their high conversion efficiency and simplicity. They are non-thermal plasma sources, able to produce a high plasma density at a relatively low gas temperature (<3000K). Recently, a new type of GA plasma source, based on the innovative reverse-vortex gas flow stabilization, has been developed, allowing for even higher conversion efficiency and lower electrode degradation. However, this type of GA has not yet been studied in detail. The aim of this project is to gain fundamental knowledge on the physical processes inside the reverse-vortex stabilized GA by means of extensive computer modeling based on the COMSOL Multiphysics Software. Initially, 1D and 2D fluid plasma models will be developed, with later extension into a 3D model. The complete 3D model will involve the plasma physics and chemistry, fluid dynamics and heat transfer.

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Atomic scale simulations for a better understanding of cancer treatment by plasmas. 01/10/2015 - 30/09/2017

Abstract

Atmospheric pressure plasmas are gaining increasing interest for biomedical applications, like sterilization, wound treatment, dental treatment, blood coagulation, and especially cancer treatment. In the latter case, plasmas have demonstrated to give very promising results, both in vitro and in vivo, and are able to attack a wide range of cancer cell lines without damaging healthy cells. However, the underlying mechanisms are not yet fully understood. I will therefore perform atomic scale simulations to study the interaction mechanisms of reactive oxygen and nitrogen species (ROS, RNS) formed in the plasma with biomolecules, present in eukaryotic cells, which play a role in cancer (treatment). More specifically, I will apply classical molecular dynamics and density functional based tight binding simulations, and I will study three types of biomolecules, which play a crucial role in cancer (treatment): (1) a phospholipid bilayer (PLB) as model system for the cell membrane, (2) a part of a DNA string and (3) peptides, as a model system for proteins. I will investigate how the ROS and RNS interact with these biomolecules, which reaction products are formed, and how this can lead to apoptosis (cell death). This research will contribute to a better understanding of the role of plasmas in cancer treatment.

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Towards a fundamental understanding of a gliding arc discharge for the purpose of greenhouse gas conversion into value-added chemicals (GlidArc). 22/06/2015 - 21/06/2017

Abstract

Global climate change due to anthropogenic greenhouse gas emissions is a growing concern. The conversion of greenhouse gases (mainly CO2, CH4) to value-added chemicals or renewable fuels is an effective strategy to reduce these emissions and an interesting process both from economic and ecological point of view. A gliding arc (GlidArc) plasma offers unique perspectives for activating inert molecules at mild conditions and allows the greenhouse gas conversion with limited energy cost. A GlidArc is, however, very complex and poorly understood. Therefore, this project intends to obtain more fundamental insight in the plasma-mechanisms of the GlidArc for greenhouse gas conversion, by means of extensive modeling, validated by experimental diagnostics.

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Sample introduction in inductively coupled plasmas: A better insight through computer modeling. 01/10/2014 - 30/09/2017

Abstract

Inductively coupled plasma mass spectrometry (ICP-MS) is a method to chemically analyze several kinds of (environmental, biological and inorganic) samples. This is achieved by ionizing the sample with an inductively coupled plasma and using a mass spectrometer to separate and quantify the ions. Because of its high sensitivity and ability to measure about 80% of the periodic table, the ICP has become one of the most popular ion sources in analytical chemistry. To improve the analytical performance, fundamental studies are indispensable. They have been carried out for several years both experimentally and computationally. However, there is a strong need for a complete model which can provide details on the sample behavior inside the plasma. This kind of detailed information is barely accessible from experiments, and computational modeling will therefore be very helpful. Thus, in this project, for the first time worldwide, I will develop a comprehensive model for ICPMS, including the behavior of the sample, and I will validate my model with experiments, in collaboration with other groups. First, I will develop a model for elemental droplets and subsequently, I will extend the model to describe samples dissolved in water (i.e., multicomponent droplets) including chemical reactions. Finally, I will apply the model to different geometries, like a dual concentric injector, to propose geometrical optimizations as well as predict the optimal operating conditions for ICP-MS.

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Computer simulations of gold-catalyzed growth of carbon nanotubes at the atomic scale. 01/10/2014 - 30/09/2017

Abstract

Recently, Au-catalyzed plasma enhanced chemical-vapor deposition (PECVD) has been shown to significantly narrow the chirality distribution. However, actual control still remains unachieved and moreover, very little is known about the underpinning fundamental mechanisms of chirality formation. In this project, I therefore envisage to use atomistic simulations to investigate these mechanisms and how these mechanisms may be controlled through the PECVD process conditions in order to obtain a definable and predictable CNT structure and chirality. I will therefore investigate the role of several plasma effects, including the electric field, plasma-generated radicals, ion bombardment and etching. By comparing Au-catalyzed CNT growth to Ni-catalyzed growth, the specific role of the catalyst in PECVD will be investigated as well.

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Towards a fundamental understanding of plasma-TiO2 catalyst interaction for greenhouse conversion. 01/10/2014 - 30/09/2016

Abstract

In this PhD project, we will build more insight in these fundamental processes on an anatase TiO2 catalyst surface, by means of state-of-the-art computer simulations. The plasma-catalyst interactions will be studied on the atomic scale by a combination of various simulations techniques. These techniques are based on an interatomic potential ("force field") that governs all atomic interactions. First, force field parameters for the Ti/O/C/H system will be developed, in collaboration with various other research groups in Flanders. Subsequently, reaction mechanisms and corresponding reaction rate coefficients for all relevant plasma species interacting with the TiO2 catalyst surface will be studied by nudged elastic band (NEB) and force biased Monte Carlo (MC) simulations. Finally, also the actual plasma catalysis process itself will be simulated by molecular dynamics (MD) and hybrid MD/MC simulations. These results will provide the necessary knowledge of the plasma/catalyst interaction, required for controlling and steering the conversion process of greenhouse gases into value-added chemicals.

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Multi-timescale atomistic modeling of plasma catalysis and plasma-based growth of carbon nanostructures. 01/10/2014 - 30/09/2016

Abstract

In this project I will develop a novel atomic scale simulation tool to unravel the fundamental mechanisms underpinning complex plasma-based processes. Specifically, I will concentrate on plasma catalysis, which is envisaged to provide an energy efficient route for greenhouse gas conversion into value-added chemicals, and plasma-based growth of carbon nanostructures, which holds promise to offer control on structure and composition, unattainable by thermal methods.

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Computer modeling for a better insight in the underlying mechanisms of plasma catalysis. 01/01/2014 - 31/12/2017

Abstract

Plasma catalysis is gaining increasing interest in environmental applications, e.g. for the conversion of greenhouse gases into value-added chemicals or new fuels. However, the fundamental mechanisms of plasma-catalyst interaction are virtually unknown. In this project, we hope to obtain more insight in these fundamental processes, by computer modeling and experimental validation.

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CO2 conversion by plasma catalysis: unraveling the influence of the plasma and the nanocatalyst properties on the conversion efficiency. 01/01/2014 - 31/12/2017

Abstract

The high CO2 concentration in the earth's atmosphere causes major concern because of its impact on climate change (global warming). In this project, we study the CO2 conversion into renewable fuels and value-added chemicals, such as CO (in case of pure CO2 splitting), syngas (CO/H2) and hydrocarbons (e.g. methanol, formic acid,…) in the case of CO2/CH4 conversion, by means of plasma catalysis. In this way, we can solve two problems in one step, as "waste" can be converted into value-added chemicals.

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Characterisation and modeling of the initial growth and stability of anisotropic Au and Au/Ag nanoparticles at the atomic scale. 01/01/2014 - 31/12/2017

Abstract

The overall goal of this project is to characterise and simulate the growth and stability of anisotropic Au and Au/Ag nanocrystals at the atomic scale. In order to reach this final objective, our intermediate technical goals are: • To experimentally determine the p osition and chemical nature of each individual atom in anisotropic Au and Au/Ag NP's. • To develop a reactive force field required for the atomistic simulations.

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Comprehensive simulations of microdischarges with a Particle-In-Cell/Monte Carlo/Direct Simulation Monte Carlo model (postdoc. fellowship Ya ZHANG, China). 01/01/2014 - 30/06/2015

Abstract

During this research fellowship, we will try to obtain a better insight by computer simulations. The latter will be compared with experimental data, obtained from literature. More specifically, a comprehensive model based on the Particle-In-Cell/Monte Carlo/Direct Simulation Monte Carlo (PIC/MC/DSMC) method will be developed and applied to simulate the behavior of a MD operating in Ar, He and ambient air, under different conditions and parameters. We will try to elucidate the fundamental physical and chemical process involved, and find the optimum parameters of a MD.

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Modeling of the plasma chemistry in CHxFy based gas mixtures for microelectronics applications. 05/10/2013 - 07/04/2014

Abstract

This project represents a formal research agreement between UA and on the other hand Erasmus Mundus. UA provides Erasmus Mundus research results mentioned in the title of the project under the conditions as stipulated in this contract.

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Reactive Atmospheric Plasma processIng - eDucation network (RAPID). 01/10/2013 - 30/09/2017

Abstract

The goal of the Multi-Partner ITN-RAPID (Reactive Atmospheric Plasma processIng - eDucation network) is the realization of an interdisciplinary training involving the disciplines physics, chemistry and engineering. As a result, RAPID will create the platform for a truly European PhD in plasma technology. The scientific goal is the development of non-equilibrium reactive processes in atmospheric pressure plasmas.

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Towards a fundamental understanding of "warm plasmas"– Conversion of greenhouse gasses to value added chemicals by gliding arc and microwave discharges. 01/10/2013 - 30/09/2014

Abstract

The main objective of this PhD project is to unravel the fundamental processes and mechanisms that occur in warm plasmas (i.e., gliding arc and microwave discharges) and which give rise to unprecedented energy-efficient reaction chemistry. I will focus on the chemical reactions of various plasma species (including neutral, charged and excited species), originating from the greenhouse gases CH4 and CO2, and on their conversion into new fuels or value-added chemicals, such as syngas (CO and H2), methanol (CH3OH), formaldehyde (CH2O) and higher hydrocarbons.

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Francqui research professor "PLASMA" 01/09/2013 - 31/08/2016

Abstract

This project represents a formal research agreement between UA and on the other hand a private institution. UA provides the private institution research results mentioned in the title of the project under the conditions as stipulated in this contract.

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Plasma chemistry modeling in a capacitively coupled plasma used for microelectronics applications. 01/04/2013 - 31/12/2013

Abstract

Plasmas are widely used in the microelectronics industry for the fabrication of computer chips, i.e., in plasma etching and deposition of different materials. Nowadays there is increased interest for the use of very complex gas mixtures, such as based on CHxFy, sometimes even in combination with HBr, Cl2 and O2. In this project, we wish to obtain a better understanding of the plasma chemistry in several CHxFy plasmas, i.e., CHF3, CH2F2 , CH3F and CF4, by means of a computer model. For this purpose, we will make use of the hybrid plasma equipment model (HPEM). A reaction set will be created, based on a large number of plasma species, including various molecules, radicals, ions, excited species, as well as the electrons. These species react with each other in a large number of collisions, namely electron-neutral, electron-ion, ion-ion, ion-neutral and neutral-neutral reactions. A list of all possible reactions will be constructed, along with the corresponding cross sections and reaction rate coefficients. Subsequently, for every plasma species the various production and loss processes need to be specified, for solving the continuity equations. The transport of the species will be described based on diffusion, migration and advection. The electric field distribution inside the plasma will be calculated self-consistently from the charged species densities by solving Poisson's equation. Typical results of this model include the species densities, fluxes and energies, the electromagnetic field distribution, and information on the importance of various reactions in the plasma.

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Mechanical properties and chemical bonding at the interfaces in polymer-based composite materials (InterPoCo). 01/03/2013 - 28/02/2017

Abstract

The main goals of the SB01 project "Mechanical properties and chemical bonding at the interfaces in polymer-based composite materiais" (InterPoCo) within the H-INT-S program are to (i) develop and apply a set of experimental and computational tools for comprehensive structural, compositional and quantitative mechanical characterisation of the interfaces in polymer-based composites at na no- and microscale level, (ii) to measure and predict structural, electronical, compositional, thermodynamica I and mechanical properties of bulk polymers and interfaces in polymer-based composites, (iii) to validate and improve the prediction reliability by emphasizing the interplay between modelling and experimental data obtained using a high-throughput approach and advanced characterisation results and (iv) to provide currently unavailable information on the above aspects to the running and future vertical SIBO programs.

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Modeling of plasma and plasma-cell interaction for a better understanding of plasma medicine applications. 01/01/2013 - 31/12/2016

Abstract

The aim of this project is to obtain a better insight in plasma-cell interactions on the atomic scale, and specifically on plasma-bacteria interactions. For this purpose, hybrid MD / Monte Carlo (MC) simulations will be performed, for the plasma species bombarding the "substrate" (i.e., bacteria) to be treated. The plasma species and their fluxes will be determined from plasma modeling. Therefore, this project is a combination of plasma modeling and modeling of plasma-bacteria interactions.

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Modeling and experimental validation of a packed bed DBD reactor for CO2 splitting. 01/01/2013 - 31/12/2016

Abstract

Global warming, for 70 % caused by CO2, is becoming a bigger problem. As a possible solution, the use of plasmas for CO2 splitting and conversion to value-added chemicals gains interest every year. In this research, the use of a packed bed DBD plasma reactor will be investigated by means of computer simulations and experimental validation. By changing the properties of the packing as well as operational conditions of the reactor, the process will be optimized, with a strong emphasis on the energy efficiency.

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IWT Post-graduate Grant. 01/01/2013 - 31/12/2014

Abstract

This project represents a research agreement between the UA and on the onther hand IWT. UA provides IWT research results mentioned in the title of the project under the conditions as stipulated in this contract.

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Physical chemistry of plasma-surface interaction (PSI). 01/10/2012 - 31/12/2017

Abstract

The project aims at federating Belgian groups involved in research activities on reactive plasmas in order to improve our fundamental understanding of these systems and to develop predictive models. The output of this project, which combines experimental and theoretical activities, is expected to drive technological developments in the area of new materials, new surfaces or new coating processes, and therefore to sustain the economic development of our country. We are developing a multidisciplinary and integrated approach, merging together the expertise of research units specialized in plasma diagnostics (optical, electrical probe, laser induced fluorescence and mass spectrometry techniques), in the fundamental study of the ionized gas phase and its hydrodynamics, in bulk plasma and plasma-surface interaction modeling (molecular dynamics, Monte Carlo) and in (organic and inorganic) material synthesis, functionalization and characterization using state-of-the-art tools.

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Numerical simulations of plasmas and their surface processes, used for microelectronics applications. 01/10/2012 - 30/09/2015

Abstract

The objectives for this project are to achieve a better insight in: 1. the fundamental plasma behavior of novel STI gas mixtures, more specifically, Cl2/O2 in combination with CF4, CHF3, CH2F2 and HBr; 2. the surface processes on the Si substrate and the reactor walls during plasma treatment, including trench profile evolution; 3. the plasma uniformity in next generation 450 mm wafer reactors.

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Towards a fundamental understanding of plasma - TiO2 catalyst interaction for greenhouse gas conversion. 01/10/2012 - 30/09/2014

Abstract

In this PhD project, we will build more insight in these fundamental processes on an anatase TiO2 catalyst surface, by means of state-of-the-art computer simulations. The plasma-catalyst interactions will be studied on the atomic scale by a combination of various simulations techniques. These techniques are based on an interatomic potential ("force field") that governs all atomic interactions. First, force field parameters for the Ti/O/C/H system will be developed, in collaboration with various other research groups in Flanders. Subsequently, reaction mechanisms and corresponding reaction rate coefficients for all relevant plasma species interacting with the TiO2 catalyst surface will be studied by nudged elastic band (NEB) and force biased Monte Carlo (MC) simulations. Finally, also the actual plasma catalysis process itself will be simulated by molecular dynamics (MD) and hybrid MD/MC simulations. These results will provide the necessary knowledge of the plasma/catalyst interaction, required for controlling and steering the conversion process of greenhouse gases into value-added chemicals.

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  • Research Project

Modelling transport of CO2 through porous structures during carbonation reaction. 01/07/2012 - 30/09/2013

Abstract

In this project, the carbonation processes leading to the production of carbonates through reaction between magnesium/calcium-rich minerals that typically occur in waste materials and carbon dioxide (C02) will be investigated by numerical modelling. The aim is to be able to optimise the parameters that influence the carbonation process in order to improve the transition of the process from lab to pilot scale.

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  • Research Project

Modeling of the fundamental physical processes in a plasma jet. 01/01/2012 - 31/12/2015

Abstract

Plasma jets are gaining increasing interest due to their promising applications in plasma medicine. In this project, we plan to study the physics and chemistry of a plasma jet through computer simulations. We will develop a numerical model, that will be built up step by step. A static plasma in a dielectric barrier discharge in pure He forms the starting point and will be described with a fluid model. This model will be extended to account for the effect of air impurities. Subsequently, a gas flow will be added to the model, by solving Navier- Stokes equations, and the formation of a jet (or flowing afterglow) will be simulated. Special attention will be paid to the behavior of the charged species, UV light and reactive oxygen species, as they play a key role in the interaction of the plasma jet with living tissue. Finally, the streamer-like propagation process of the plasma jet will be investigated. For this purpose, the behavior of the electrons will be simulated by a Monte Carlo model, and the photons will be treated with a model describing radiation transport. In this way, we hope to elucidate the fundamental physics behind plasma propagation of the plasma jet.

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  • Research Project

Plasma intensifaction in DBD plasma devices by the use of a packed bed of ceramic particles with specific dielectric properties, obtained by a core-shell design and by specific tuning of the particle size distribution (i-PLASMA). 01/01/2012 - 31/12/2013

Abstract

Study of the use of core-shell and particle size distribution designed dielectric ceramic particles as packed bed material in the intensification of plasma based chemical processes. Experience in the field of industrial plasma generation will be combined with the modelling expertise of PLASMANT, in order to check on the valorisation potential of plasma induced chemistry. A dedicated experimental/empirical dataset will be set up and a related CIT process analysis. Valorisation is situated in emission control and synthesis of alternative raw material starting from waste streams.

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  • Research Project

Computer modelling of plasmas used for etching applications in the microelectronics industry (postdoc.beurs S. ZHAO, China). 15/10/2011 - 14/12/2012

Abstract

Because of the important use of gas discharge plasmas in the microelectronics industry, a good insight in the plasma behavior is desirable. During the research fellowship we will try to obtain this insight by computer simulations. The latter will be compared with experimental data, obtained at her home institution, i.e., Dalian University of Technology.

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  • Research Project

Computer modelling of an atmospheric pressure glow discharge with flowing afterglow. 01/10/2011 - 30/09/2012

Abstract

A glow discharge (GD) is a partially ionized gas. It consists of neutral atoms or molecules, electrons, ions, radicals, excited species and photons. In its most simple form it is created by applying a potential difference between two electrodes, placed in a reactor, which is filled by a gas. Most of the GDs operate at reduced pressure, however, atmospheric pressure glow discharges (APGDs) are gaining increasing interest due to their wide range of technological applications. In the current research project, we envisage the application in analytical mass spectrometry, for the analysis of solids or gaseous samples. Operating the GD at atmospheric pressure makes it possible to open the design and to mix the discharge species with ambient air. Applying a gas flow helps to draw the metastables and ions out of the discharge and to prevent the entering of impurities. The ions and metastables react with air constituents and reagent ions are formed, which are then capable of ionizing the analytes. The ions of the analytes are detected by a mass spectrometer. The aim of this project is to reveal the main mechanisms of reagent ion formation and to improve the analytical capabilities of this sort of ionization sources.

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  • Research Project

Atomistic simulations of plasma-enhanced chemical vapor deposition of single walled carbon nanotubes 01/07/2011 - 31/12/2015

Abstract

Single walled carbon nanotubes ("SWNTs") are hollow cylindrical structures consisting of a hexagonal carbon network. Their unique properties, such as extreme strength, very high thermal conductivity and structure dependent bandgap, offer perspective on various applications, in e.g. nanoelectronics, as chemical sensors or as induced field emitters. Such applications, however, require precise control over fundamental properties of the SWNTs. This control is currently lacking. Especially control over the chirality of the SWNT, which is directly responsible for the bandbap, is desired. Plasma-enhanced chemical vapor deposition ("PECVD") is regarded as one of the most promising deposition tools to accomplish this control. However, the underlying fundamental growth mechanisms are largely unknown. In this project, we therefore wish to investigate various PECVD-specific processes and process parameters in order to gain insight in the growth mechanisms, aiming at gaining control over the resulting SWNT properties. We wish to accomplish this goal by using a state-of-the-art hybrid Molecular Dynamics / force biased Monte Carlo simulation model, that allows us to simulate self-consistently all relevant processes at the atomic scale. Specifically, we plan (i) to optimize the existing simulation model in order to reduce the required computation time and extend the model to PECVD-growth; (ii) to perform specific simulations to simulate the growth of SWNTs under realistic (PECVD) process conditions on nickel nanocatalysts; (iii) to perform parameter studies that allow us to investigate the effect of the variation of precisely one parameter at a time, in order to determine how we can influence the growth process; and (iv) to develop a force field parametrization for Ni/Fe alloys to be used in the interatomic potential, and subsequent simulation of the PECVD-growth of SWNTs on Ni/Fe nanocatalysts. The innovative character of this project consists of (i) the use of the accurate interatomic potential in combination with the use of the hybrid MD/MC model that takes into account both short time scale as well as long time scale events; (ii) the study of SWNT growth in a PECVD-setup by means of atomistic simulations; and (iii) de development and application of Ni/Fe force field parameters for the simulation of PECVD-growth of SWNTs on Ni/Fe nanocatalysts. Although this project is indeed very innovative (both regarding the used methodology as the goals we are aiming for), we believe that this project is very feasible: indeed, we have already proven the effectivity of the simulation model in simulating the growth of SWNTs under thermal CVD conditions. Furthermore, we have access to all required tools needed to simulate the PECVD-specific process conditions. We therefore believe that we will be able to unravel fundamental processes in PECVD growth of SWNTs and to gain insight in this promising but until now at the atomic level nearly unexplored process.

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  • Research Project

Computer modeling for the destruction of volatile organic compounds by means of (catalytic packed bed) DBD plasma reactors. 01/04/2011 - 31/03/2015

Abstract

In this project we wish to obtain a better insight in the destruction of volatile organic compounds (VOC's) in (catalytic packed bed) plasma reactors. By means of computer simulations and experimental validation, we will try to understand and optimize the different steps in the entire project with respect to the influence of the general reactor design, as well as a packing and a catalyst.

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  • Research Project

Numerical simulations of plasma jets used for biomedical applications. 01/01/2011 - 31/12/2014

Abstract

Plasma Jets are gasdischarges which can be used for various biomedical and therapeutic applications such as sterilization, dermatology, blood coagulation, wound care and dentistry, which resulted in the last decade in a rapidly growing international interest. However, before such technologies may be brought on the market the efficiency, safety, selectivity and reproducibility has to be ensured. A good knowledge of the role of biomedically active elementsin the plasma , e.g. radicals, ions, radiation etc., is extremely important. The objective of this work is to study the mechanisms of various plasma jet configuration and the plasma-tissue interactions, specifically for application optimization. Trough numerical simulations, we will make the advantages and disadvantages of different configurations and discharge conditions clear. The calculations will be performed with the fluid model "nonPDPSIM" developed by the research group of Prof. M. Kushner (University of Michigan). Moreover, we will cooperate with two experimental research groups: Rupt (Universiteit Gent, Prof. C. Leys) and EPG (TU Eindhoven, Prof. P. Bruggeman) to verify our modeling work.

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  • Research Project

Computer modeling and experimental validation for plasmas used for etching in the microelectronics industry. 01/10/2010 - 30/09/2012

Abstract

Computer simulations will be performed for describing the plasma chemistry and physics in two reactors used for etching in the microelectronics industry, i.e., inductively coupled plasmas (ICP) and dual frequency capacitively coupled plasmas (CCP). Several fluorocarbon-based gas mixtures will be considered. The effect of different operating conditions (pressure, gas ratio, power, frequency,. . .) will be investigated to predict under which conditions both discharges have optimum performance. Experimental validation of the calculations will be carried out in both types of reactors. Finally, the effect of these operating conditions on the trench formation, the etch rate, uniformity, selectivity and anisotropy will be investigated.

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  • Research Project

Numerical simulations on the atomic scale of nanotechnological C- and Si-materials. 01/10/2010 - 30/11/2011

Abstract

In this project, we wish to investigate the fundamental formation processes that give rise to specific carbon and silicon nanomaterials: (ultra)nanocrystalline diamond, carbon nanotubes, amorphous hydrogenated carbon, and nanocrystalline silicon. The objective is gaining control over their structure in order to tune their properties making them suitable for real life applications. This requires insight into the relevant mechanisms on the atomic scale. Therefore, we will perform atomistic simulations of the growth process under realistic growth conditions, in strong collaboration with experimental groups for validation and further model improvements.

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  • Research Project

Computer modeling of the plasma chemistry in gas discharges for environmental or biomedical applications. 10/08/2010 - 09/06/2011

Abstract

The goal of the research project is to apply fluid modeling for describing the plasma chemistry in an atmospheric pressure plasma, used for environmental and biomedical applications, in order to improve these applications.

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  • Research Project

Numerical simulations of inductive coupled plasma' s uses for etch processes. 01/01/2010 - 31/12/2011

Abstract

In this project we try to obtain a better insight in an inductively coupled plasma (ICP) operating in a Cl2/Ar/O2 gas mixture, as well as in the etch process of this plasma on a Si and Si/Si3N4 surface, to optimize the applications of plasma etching in the semiconductor industry. To realize this aim, we wish to describe the plasma and the etch process by numerical simulations. We make use of an hybrid plasma model in combination with a model for surface reactions.

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  • Research Project

Atomic simulations for chirality-controlled increase of carbon nanotubes. 01/01/2010 - 30/06/2011

Abstract

In this project we try to obtain a better insight in the growth mechanisms of the catalyzed growth of single-wall carbon nanotubes (SWNTs), by means of numerical simulations. The simulations are based on classical molecular dynamics (MD) and Monte Carlo (MC) simulations, complemented by quantum mechanical density functional theory (DFT). We try to elucidate the relationschip between specific growth parameters (such as temperature, composition and growth of the catalyst) and the chirality of the SWNTs. In this way, we hope to enable the chirality-controlled growth of the CNTs, which is of great importance for industrial applications (e.g., in the micro-electronics industry).

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  • Research Project

Study of plasma-surface interactions, by molecular dynamics simulations, for applications of plasma-etching and plasma-deposition. (FWO Vis.Fel., Fujun GOU, China) 01/02/2009 - 31/01/2010

Abstract

In this project plasma-surface interactions will be studied by molecular dynamics simulations, for applications of plasma-etching (of Si/SiO2 surfaces in the micro-electronics industry) and for plasma-deposition of thin films.

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  • Research Project

Computational modeling of materials. 01/01/2009 - 31/12/2013

Abstract

In this "Scientific Research Community" we try to calculate the properties of materials by computer simulations. More specifically we study the growth of thin films and of carbon nanotubes by molecular dynamics simulations. By contact with the other research groups we hope to share and exchange our expertise.

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  • Research Project

Reactive magnetron sputter deposition : a hybrid model and its experimental verification. 01/01/2009 - 31/12/2012

Abstract

Basic aspects of the project "Reactive magnetron sputter deposition : a hybrid model and its experimental verification": This project aims at the development of a hybrid model for the description of the reactive sputter process. This goal shall be reached by a combination of simulations and experiments.

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  • Research Project

Atomistic multi-time scale simulations of catalyzed carbon nanotube growth 01/01/2009 - 31/12/2012

Abstract

This research project aims at bringing atomistic simulations closer to experimental conditions by developing realistic interatomic M-C-H interaction potentials and implementing long-time scale algorithms.

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  • Research Project

Combined Molecular Dynamics (MD) and Monte Carlo (MC) simulations for the plasma-enhanced deposition of (ultra)nanocrystalline diamond ((U)NCD) films. 01/01/2009 - 31/12/2010

Abstract

We wish to study the deposition process of (ultra)nanocrystalline diamond films, formed by microwave plasmas, by means of molecular dynamics simulations. We will use the Brenner interaction potential for hydrocarbons. To simulate the deposition process in a realistic way, we wish to develop also Monte Carlo simulations, to describe the relaxation of the system to a thermodynamically more favorable configuration. These Monte Carlo simulations will be coupled to the molecular dynamics simulations. We wish to investigate, among others, the influence of substrate temperature, applied bias to the substrate and gas mixture.

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  • Research Project

Plasma-assisted conversion of greenhouse gases to value-added chemicals 01/02/2008 - 31/01/2012

Abstract

The aim of this project is to convert greenhouse gases, such as CH4, CO2 en N2O, into value-added chemicals, such as methanol, by means of plasmas, either or not in combination with catalysis. This proces is very difficult to realize under normal conditions, because these greenhouse gases are very inert molecules. In plasmas energetic electrons are formed, which can induce these conversions. New plasma reactors will be developed and tested for a wide range of parameters. Our specific role in the project are the numerical simulations of the plasma chemistry, to support the experimental studies and to predict the optimal process conditions.

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Project type(s)

  • Research Project

Numerical simulations of inductive coupled plasma' s uses for etch processes. 01/01/2008 - 31/12/2009

Abstract

In this project we try to obtain a better insight in an inductively coupled plasma (ICP) operating in a Cl2/Ar/O2 gas mixture, as well as in the etch process of this plasma on a Si and Si/Si3N4 surface, to optimize the applications of plasma etching in the semiconductor industry. To realize this aim, we wish to describe the plasma and the etch process by numerical simulations. We make use of an hybrid plasma model in combination with a model for surface reactions.

Researcher(s)

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Project type(s)

  • Research Project

Atomic simulations for chirality-controlled increase of carbon nanotubes. 01/01/2008 - 31/12/2009

Abstract

In this project we try to obtain a better insight in the growth mechanisms of the catalyzed growth of single-wall carbon nanotubes (SWNTs), by means of numerical simulations. The simulations are based on classical molecular dynamics (MD) and Monte Carlo (MC) simulations, complemented by quantum mechanical density functional theory (DFT). We try to elucidate the relationschip between specific growth parameters (such as temperature, composition and growth of the catalyst) and the chirality of the SWNTs. In this way, we hope to enable the chirality-controlled growth of the CNTs, which is of great importance for industrial applications (e.g., in the micro-electronics industry).

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  • Research Project

Combined numerical simulations of the growth of nanoparticles in reactive plasmas and the deposition of nanomaterials. 01/10/2007 - 30/09/2010

Abstract

The aim of this project is to obtain a better insight, by means of numerical simulations, in the behavior of reactive carbon-based plasmas, used for the formation and deposition of nanostructured carbon films and nanomaterials (such as (U)NCD and CNT), as well as about the formation process of the nanomaterials itself. We wish to describe in a fully integrated way the formation, growth and behavior of the nanoparticles in the plasma, the interaction of these particles with the substrate and the walls, and the formation of the nanomaterials.

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  • Research Project

Growth of Complex Oxides. 01/06/2007 - 31/05/2012

Abstract

The project targets to understand the growth of complex oxide thin films by a detailed characterisation and modelling of the process. The relaxation between a number of layer properties and intrinsic properties of the layers will be evaluated.

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  • Research Project

GLADNET - Analytical glow discharge network. 01/02/2007 - 31/01/2011

Abstract

The GLADNET Consortium aims at integrating teams working on particular aspects in groups in Physics, Chemistry or Material Science departments, concentrating on the discharge physics and spectroscopy, the analytical chemistry or the structure of materials and teams working in industry on particular applications and instrument development and to provide open training facilities for the next generation of researchers in the field. The specific role of the research group PLASMANT is to develop numerical models for the glow discharge plasma, especially to describe the effect of hydrogen, nitrogen or oxygen gas impurities on the argon plasma.

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  • Research Project

Quantum effects in clusters and nanowires. 01/01/2007 - 31/12/2011

Abstract

In this project the physical properties of individual nanoparticles and nanowires will be investigated. The main activities will be concentrated on nanowires, quantum dots, clusters and nanostructured thin films. The nanosystems will be composed of either semiconductors, metals (e.g. superconductors or ferromagnets), carbon, oxides, organic materials and combinations of these materials. The latter are also called hybrid systems, and give extra flexibility to the properties of the nanosystems.

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  • Research Project

Growth, characterisation an simulation of nanocrystalline and ultrananocrystalline PE-CVD diamond films. 01/01/2007 - 31/12/2010

Abstract

The aim of the project is the experimental and theoretical study of the growth of nanocrystalline and ultrananocrystalline PE-CVD diamond films, as well as the structural, morphological and (opto)electronic characterisation of these films. The project can be divided in three main parts, which are strongly correlated: A. deposition of NCD and UNCD films B. structural, morphological and (opto-)electronic characterisation C. simulation of the deposition of NCD and UNCD films

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  • Research Project

Combined Molecular Dynamics (MD) and Monte Carlo (MC) simulations for the plasma-enhanced deposition of (ultra)nanocrystalline diamond ((U)NCD) films. 01/01/2007 - 31/12/2008

Abstract

We wish to study the deposition process of (ultra)nanocrystalline diamond films, formed by microwave plasmas, by means of molecular dynamics simulations. We will use the Brenner interaction potential for hydrocarbons. To simulate the deposition process in a realistic way, we wish to develop also Monte Carlo simulations, to describe the relaxation of the system to a thermodynamically more favorable configuration. These Monte Carlo simulations will be coupled to the molecular dynamics simulations. We wish to investigate, among others, the influence of substrate temperature, applied bias to the substrate and gas mixture.

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  • Research Project

Numerical simulations of dielectric barrier discharges equipped with a gas flow and a flowing afterglow which are used for the deposition of thin SiO2-layers. 01/01/2007 - 30/09/2007

Abstract

A fluid model will be developed for a dielectric barrier discharge, used for the deposition of SiO2 thin films. This discharge operates in a mixture of argon + oxygen, in which HMDSO is introduced as a precursor for the SiO2 layers. The chemistry in the plasma will be described in detail with the model. Moreover, the effect of a gas flow, to stabilize the discharge, will be investigated.

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  • Research Project

Numerical simulations of an inductively coupled plasma used for etching practices. 01/10/2006 - 30/09/2010

Abstract

The aim of this project is to obtain a better insight in an inductively coupled plasma (ICP) operating in a Cl2/Ar/N2 gas mixture, as well as in the etch process of this plasma on a Si and Si/Si3N4 surface, to optimize the applications of plasma etching in the semiconductor industry. To realize this aim, we wish to describe the plasma and the etch process by numerical simulations.

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  • Research Project

Numerical investigation of the growth and deposition processes of nanoparticles in reactive gas discharges, used for nanotechnology applications. 01/10/2006 - 15/11/2006

Abstract

The aim of this project is to obtain a better insight, by means of numerical simulations, in the behavior of reactive silane and hydrocarbon (e.g., methane, acetylene) plasmas, used for the deposition of thin films. We wish to describe in a fully self-consistent way the formation, growth and behavior of nanoparticles in the plasmas, as well as the growth of so-called polymorphous hydrogenated silicon films and (ultra)nanocrystalline diamond films. Especially the incorporation of the nanoparticles in these films will be investigated.

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  • Research Project

Development of a "particle-in-cell Monte Carlo" model for pulsed magnetron discharges, used for the reactive sputter-deposition of nitride- and oxide-layers. 01/07/2006 - 31/12/2010

Abstract

The aim of the project is the modeling of pulsed magnetron discharges, in a mixture of argon with nitrogen or oxygen, used for the reactive sputter-deposition of nitride- or oxide-layers, respectively. The magnetron plasma will be modeled with a particle-in-cell ¿ Monte Carlo model. The influence of, among others, the gas ratio (i.e., reactive gas to argon) will be studied.

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  • Research Project

BOF/IWT-fellowship for the project "Fluid modeling of a dielectric barrier discharge, used for the deposition of SiO2 layers". 01/01/2006 - 31/12/2006

Abstract

In this project we try to develop a fluid model for a dielectric barrier discharge in a mixture of argon + oxygen, with the precursors HMDSO (hexamethyldisiloxane) or TEOS (tetraethoxysilane), used for the plasma deposition of siliciumdioxide (SiO2) layers. The plasma chemistry of both precursors will be extensively studied. Next, the influence of an external gas flow on the discharge behavior will be investigated, by coupling of the fluid model to a commercial "computational fluid dynamics" (CFD) program "FLUENT". Finally, the formation and behavior of a so-called flowing afterglow, as a result of a high gas flow, will be simulated.

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  • Research Project

Nucleation and durability of very thin CVD oxide films on steel and metallic coated steel. 01/10/2005 - 30/03/2008

Abstract

The deposition mechanism of very thin oxide films, deposited by chemical vapor deposition (CVD) on steel and metallic coated steel, is being studied by experiments and computer simulations. Our task within the project is focused on the computer simulations. We are developing a molecular dynamics (MD) model, that gives a detailed description of the deposition process. This model iwill be coupled to a Monte Carlo model, for description of the relaxation of the surface during deposition. We also wish to study the mechanism of nucleation.

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  • Research Project

Particle-in-Cell/Monte Carlo Collision model for a pulsed magnetron discharge, used for the reactive sputter-deposition of nitride- and oxide-layers. 01/10/2005 - 30/09/2007

Abstract

We are developing a particle-in-cell/Monte Carlo collision model for a pulsed magnetron discharge, in a mixture of argon+nitrogen, or argon+oxygen, for the description of the reactive sputter-deposition of nitride or oxide layers, respectively. In first instance, the model will be developed for a direct current (dc) magnetron discharge, and the chemical reactions between the various plasma species will be described. Subsequently, the model will be extended to a pulsed discharge. We wish to compare the model results with experiments, carried out by other research groups.

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  • Research Project

Modeling of micrometer-sized particle formation in laser ablation of solid materials. (FWO Vis. Fel., D. BLEINER) 01/09/2005 - 31/08/2006

Abstract

A model will be developed to describe the processes occurring during laser ablation (LA) of solids, to improve the application of LA for ICP-analysis. Specifically the mechanisms for micrometer-sized particle formation will be simulated, based on the formation of a "melt pool" by heating of the solid. Liquid splashing of the melt pool will result in the formation of jets, which will break up in micrometer-particles. This will be described with a fluid dynamics model.

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  • Research Project

Structural and chemical characterization of materials at the micro- and nanometer scale. 01/01/2005 - 31/12/2014

Abstract

The study of surfaces, interfaces, microscopic and even nanoscopic structures becomes more and more important in the characterization of very diverse materials in metallurgy, microelectronics, optoelectronics, photographic sciences etc. This characterization is mostly carried out using so-called (micro)beam techniques. By interaction of a "primary" beam (electrons, photons, ions), "secondary" signals are generated at the material's surface (electrons, photons, ions, neutrals), which contain information on the composition and/or structure of the material's surface. The various techniques differ in the kind of information, i.e. information depth, depth resolution, possibility to measure depth profiles, lateral resolution, compatibility with certain types of materials (electrical insulator vs. conductor, refractory vs. labile material), destructive or non-destructive character and type of information (elemental, istopic, molecular) It is clear that one method cannot answer all questions. Moreover, the required equipment is very expensive It is not possible for one research group to have in-house all infrastructure, accessories, know-how, know-why, and experienced personnel. Cooperation is therefore a must. The scientific research community aims at facilitating mutual consultations, exchanges and access to complementary equipment for solving a variety of problems, introduced by one or more of its members.

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  • Research Project

Numerical simulations of processes occurring and after laser-solid interaction. 01/01/2005 - 31/12/2008

Abstract

Laser ablation (LA) is used in several application fields, among others, materials technology (i.e., deposition of layers and production of nanoparticles) and analytical chemistry (e.g., in LIBS, MALDI or as sample introduction method for the ICP). The aim of our research is to obtain a better insight in the processes occurring during and after laser-solid interaction, which might help to improve the applications. In the frame of this project, we will focus mainly on the application of LA as sample introduction method for the ICP, either used for ICP-MS or ICP-OES. For this purpose, we try to develop a numerical model, to describe the processes that occur during and after laser-solid interaction. This model incorporates: * laser-solid interaction (heating, melting, vaporization) * expansion of evaporated material (plume) in a background gas * formation of a plasma in this expanding material plume * interaction between laser and plasma * formation of nanoparticles through condensation in the expanding material plume * formationg of micrometer-sized particles through laser-solid interaction : splashing of droplets of molten material, explosive boiling.

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  • Research Project

Numerical modeling of the interactions of femtosecond and nanosecond laser pulses with a solid and with plasma. 01/01/2005 - 31/12/2006

Abstract

We try to model the interaction of laser pulses with solid or plasma. The model includes: * laser-solid interaction: heating, melting, vaporization * expansion of the metal vapor in a background gas * formation of a plasma in the material plume * interaction between laser and plasma

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  • Research Project

Modelling of the formation and behavior of dust in a radio-frequent silane discharge. 01/01/2005 - 30/09/2006

Abstract

1. FORMULATION OF THE PROBLEM Low pressure radio-frequency discharges are widely used for dry etching of semiconductor components and for thin layer deposition. Most processing gases used in industrial applications (eg. SiH4) are reactive gases and contain dust particles. Knowledge of the plasma species densities (electrons, positive and negative ions, various molecules and radicals, dust particles) together with a good understanding of their behavior in the discharge is essential from the point of view of optimization of surface processes. Initially dust grains were solely considered harmful, because they contaminated the substrate. In the microelectronics industry, particles with diameter as small as tens of nanometers may cause killer defects. Therefore, initially the research aimed at avoiding the particle formation and/or contamination. Since then this field has been rapidly expanding. It appears that film deposition in solar cells application now even benefits from the presence of nanoparticles. It was found that if particles were deposited in the films, while their size was still small, the films show improved properties. The so-called polymorphous silicon thin films have superior electric properties ' thus making this material a good candidate for use in high-efficiency solar cells. 2. METHODOLOGY In this thesis a one-dimensional numerical model will be developed to investigate the formation and behavior of dust particles in a radio-frequent silane (SiH4) plasma. A number of modelling studies of dusty plasmas have been published recently. Attempts have been made to understand the charging of dust, the forces acting on the dust particles and dust-plasma interactions. None of these, however, fully explain the mechanism behind the dust formation and its influence on plasma parameters. Theoretical and numerical studies up to now have basically followed single dust particles in the electric field and particle fluxes of an undisturbed discharge. An important aspect not covered is the influence of the dust on the discharge. For this a fully self-consistent model is needed. In this thesis a 1-dimensional fluid model will be developed for a radio frequency discharge in silane containing dust. In this model the particle balances, the electron energy balance, and the Poisson equation will be solved, including the transport of the dust fluid. The problem can be divided in different steps and contains the following procedures: - a detailed chemistry model will indicate particle growth: reactions leading to the formation of bigger anions and eventually to nanometer sized clusters will be included. In a SiH4 discharge small clusters are formed in situ: macromolecules and small crystallites are produced as a result of plasma polymerization. - a detailed description of the charge distribution of the dust particles. Dust particles generally charge up negatively to several hundreds to thousands of e (elementary charge) to balance electron and ion currents to the particles. The electrons are more mobile, which requires the particles to acquire negative potentials so that the sum of the currents remains equal. Because the dust particles are charged negatively, they respond to electric fields. - an insertion of transport equations which describe the movement of dust particles in the discharge. The particles in the plasma are subject to several forces that act either to confine them in the plasma i.e., the electrostatic force, or to drag them to the walls i.e., gravity, ion and neutral drag and the thermophoretic force. The aim of our work is to obtain a better understanding of particle behavior, to find ways to control particle contamination or increase incorporation into films, when desirable.

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Prize "Robert Oppenheimer" 2004. 01/12/2004 - 31/12/2006

Abstract

This scientific prize was given for my general scientific activities.

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  • Research Project

Mathematical simulation of the deposition of diamond-like carbon (DLC) films. 01/01/2004 - 31/12/2005

Abstract

In this project, computer simulations are performed to investigate the deposition of thin diamond-like carbon (DLC) films. In a first step, molecular dynamics (MD) simulations are used to study chemisorption reactions taking place during DLC-deposition. Molecular dynamics are based on the use of a suitable interatomic potential, from which the forces on all atoms in a system of atoms are calculated in a self-consistent way. The atom's spatial trajectory, as governed by Newtons laws, is integrated explicitly in time. Therefore, using this type of simulations, detailed information regarding film growth, growth mechanisms and film structure on the atomic level can be obtained. In a second step, physisorption is included by changing the interatomic potential, such that it is suited both for chemisorption and physisorption. Finally, diffusion of particles at the substrate will also be included. This can be done by so-called time-dependent Monte Carlo (TDMC) calculations. A TDMC model will be developed, and coupled to the MD model. Ultimately, this will lead to a model which is capable of simulating DLC film.

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  • Research Project

Simulation of the deposition of diamond-like carbon layers, using combined molecular dynamics and Monte Carlo simulations. 01/08/2003 - 31/07/2004

Abstract

In this research project, we try to simulate the plasma deposition of diamond-like carbon layers, by combined molecular dynamics (MD) en Monte Carlo (MC) simulations. MD simulations describe the behavior of individual atoms in a system. The trajectory of the atoms, under the influence of the forces resulting from the other atoms, is calculated as a function of time. The forces are obtained from the interatomic potentials. The deposition process is simulated by following a large number of particles (radicals, ions,') bombarding the surface, and by calculating the interaction with the surface atoms. This MD method is very reliable, but its major disadvantage is the long calculation time. Indeed, a typical timestep in MD simulations is in the order of 10-15 s, whereas certain processes in the deposition mechanism, e.g., diffusion of the atoms over the surface, occur on a timescale of ca. 10-6 s. Therefore, we wish to extend the MD code with a MC model, to take diffusion into account. The diffusion process will be simulated based on 'jumps', calculated in the MC model, using input data (interaction potential) from the MD model.

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  • Research Project

Modelling of the formation and behavior of dust in a radio-frequent silane discharge. 01/01/2003 - 31/12/2004

Abstract

1. FORMULATION OF THE PROBLEM Low pressure radio-frequency discharges are widely used for dry etching of semiconductor components and for thin layer deposition. Most processing gases used in industrial applications (eg. SiH4) are reactive gases and contain dust particles. Knowledge of the plasma species densities (electrons, positive and negative ions, various molecules and radicals, dust particles) together with a good understanding of their behavior in the discharge is essential from the point of view of optimization of surface processes. Initially dust grains were solely considered harmful, because they contaminated the substrate. In the microelectronics industry, particles with diameter as small as tens of nanometers may cause killer defects. Therefore, initially the research aimed at avoiding the particle formation and/or contamination. Since then this field has been rapidly expanding. It appears that film deposition in solar cells application now even benefits from the presence of nanoparticles. It was found that if particles were deposited in the films, while their size was still small, the films show improved properties. The so-called polymorphous silicon thin films have superior electric properties ' thus making this material a good candidate for use in high-efficiency solar cells. 2. METHODOLOGY In this thesis a one-dimensional numerical model will be developed to investigate the formation and behavior of dust particles in a radio-frequent silane (SiH4) plasma. A number of modelling studies of dusty plasmas have been published recently. Attempts have been made to understand the charging of dust, the forces acting on the dust particles and dust-plasma interactions. None of these, however, fully explain the mechanism behind the dust formation and its influence on plasma parameters. Theoretical and numerical studies up to now have basically followed single dust particles in the electric field and particle fluxes of an undisturbed discharge. An important aspect not covered is the influence of the dust on the discharge. For this a fully self-consistent model is needed. In this thesis a 1-dimensional fluid model will be developed for a radio frequency discharge in silane containing dust. In this model the particle balances, the electron energy balance, and the Poisson equation will be solved, including the transport of the dust fluid. The problem can be divided in different steps and contains the following procedures: - a detailed chemistry model will indicate particle growth: reactions leading to the formation of bigger anions and eventually to nanometer sized clusters will be included. In a SiH4 discharge small clusters are formed in situ: macromolecules and small crystallites are produced as a result of plasma polymerization. - a detailed description of the charge distribution of the dust particles. Dust particles generally charge up negatively to several hundreds to thousands of e (elementary charge) to balance electron and ion currents to the particles. The electrons are more mobile, which requires the particles to acquire negative potentials so that the sum of the currents remains equal. Because the dust particles are charged negatively, they respond to electric fields. - an insertion of transport equations which describe the movement of dust particles in the discharge. The particles in the plasma are subject to several forces that act either to confine them in the plasma i.e., the electrostatic force, or to drag them to the walls i.e., gravity, ion and neutral drag and the thermophoretic force. The aim of our work is to obtain a better understanding of particle behavior, to find ways to control particle contamination or increase incorporation into films, when desirable.

Researcher(s)

  • Promoter: Gijbels Renaat
  • Co-promoter: Bogaerts Annemie
  • Fellow: De Bleecker Kathleen

Research team(s)

Project type(s)

  • Research Project

Mathematical simulation of a radiofrequent capacitively coupled CH4/H2-plasma and the deposition of diamond-like-carbon (DLC) films. 01/01/2002 - 31/12/2003

Abstract

A low-pressure CH4/H2 plasma will be simulated using a combined fluid / Monte Carlo model. This model yields data like the flux and energy of particles impinging on a substrate. These impinging particles lead to diamand-like carbon film growth. This film growth will be simulated using a Molecular Dynamics model. Also, we will combine the plasma model and the film growth model. The goal is to gain insight into the underlying mechanisms of film growth, and to obtain information about the resulting film, as its structure and composition.

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  • Research Project

Modelling of a dielectric barrier discharge for reactive surface treatment. 01/11/2001 - 31/10/2005

Abstract

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  • Research Project

Physicochemical study of plasma processes in metal vapour ion lasers via numerical simulations. 01/01/2001 - 31/12/2004

Abstract

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  • Research Project

Dynamics, evolution and limitation of heavy metals water pollution in the Plovdiv Region (Bulgaria). 01/01/2001 - 31/12/2003

Abstract

A number of water sources will be sampled and analysed for heavy metals by a variety of analytical techniques. Modelling of groundwater flow in the geological formations will be used to study and predict the extension of the pollution, and to attempt to limit this.

Researcher(s)

  • Promoter: Gijbels Renaat

Research team(s)

Project type(s)

  • Research Project

Diagnostics and modelling of non-thermal high pressure plasmas. 11/12/2000 - 11/12/2003

Abstract

Researcher(s)

  • Promoter: Gijbels Renaat

Research team(s)

Project type(s)

  • Research Project

Development of technology and software for diamond-like carbon deposition in large scale plasma reactors. 01/12/2000 - 30/11/2003

Abstract

DLC (diamond-like carbon) films are considered as promising protective low-friction surface coatings with remarkable industrial impact. PE-CVD (plasma enhanced chemical vapor deposition) is a very promising technique for the deposition of DLC films. For industrial applications, it is necessary to develop PE-CVD reactors that allow the deposition of films with the required properties, with a high productivity and high growth rates on flat and non-flat substrates. At present, there are no large-scale reactors that meet all industrial requirements. Moreover, the understanding of plasma-chemical processes, the film growth mechanisms, the correlation between both, and how they change with up-scaling of the installations is far from complete for large scale (LS) PE-CVD reactors. Therefore, the main goal of the project is to develop a scientific method for the up-scaling of plasma reactors. The objectives are: 1) Experimental study of the plasma parameters and their influence on the deposition process in different PE-CVD reactors. 2) Modeling of the deposition process, (i) to simulate the effects of up-scaling of the reactors, and (ii) to predict the uniformity of coatings on samples of complex geometry. 3) Based on the theoretical and experimental studies, the development of the most appropriate LS reactor and the technology of carbon deposition on industrial samples.

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  • Research Project

Numerical simulations of glow discharges used in analytical chemistry and for laser applications. 01/10/2000 - 30/09/2004

Abstract

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  • Research Project

Secondary ion mass spectrometry using mono and polyatomic primary ions: a fundamental study of organic and inorganic ion formation and optimization of surface analysis and depth profiling. 01/01/2000 - 31/12/2003

Abstract

Static SIMS aims at characterizing organic molecules in the outer monolayer of a solid. and their interaction with the underlying "substrate". Apart from monoatomic primary ions also polyatomic primary ions will be used, e.g. SP5+, CF3+ since higher ionization yields can be obtained, esp. for high masses. Also polymers will be studied, e.g. polyurethanes, polycarbonates, fluorinated polymethacrylates and polyfosfazenes (collab. with Univ. Ghent). In "dynamic SIMS" depth profiles are measured, e.g. in semiconductor structures. Polyatomic primary ions (e.g. SF5+, Aun-) allow to improve depth resolution. The fundamental physics of polyatomic ion bombardment will also be studied in a combined SIMS-Rutherford backscattering set-up (IMEC).

Researcher(s)

  • Promoter: Gijbels Renaat
  • Co-promoter: Adriaens Mieke
  • Co-promoter: Van Vaeck Luc

Research team(s)

Project type(s)

  • Research Project

Structural and chemical characterization of materials at the micro- and nanometer scale. 01/01/1999 - 31/12/2003

Abstract

The study of surfaces, interfaces, microscopic and even nanoscopic structures becomes more and more important in the characterization of very diverse materials in metallurgy, microelectronics, optoelectronics, photographic sciences etc. This characterization is mostly carried out using so-called (micro)beam techniques. By interaction of a "primary" beam (electrons, photons, ions), "secondary" signals are generated at the material's surface (electrons, photons, ions, neutrals), which contain information on the composition and/or structure of the material's surface. The various techniques differ in the kind of information, i.e. information depth, depth resolution, possibility to measure depth profiles, lateral resolution, compatibility with certain types of materials (electrical insulator vs. conductor, refractory vs. labile material), destructive or non-destructive character and type of information (elemental, istopic, molecular) It is clear that one method cannot answer all questions. Moreover, the required equipment is very expensive It is not possible for one research group to have in-house all infrastructure, accessories, know-how, know-why, and experienced personnel. Cooperation is therefore a must. The scientific research community aims at facilitating mutual consultations, exchanges and access to complementary equipment for solving a variety of problems, introduced by one or more of its members.

Researcher(s)

  • Promoter: Gijbels Renaat

Research team(s)

Project type(s)

  • Research Project

High beam quality UV lasers for microelectronica. 01/01/1999 - 31/12/2003

Abstract

In microlithographic processes, narrow bandwidth excimer lasers are needed to bring down the scale of the structure into or below the 100 nm range. For this purpose, further narrowing of the bandwidth of the excimer lasers would be needed. The aim of this project is to develop laser systems where hollow cathode laser pulses (of CW gas laser beam quality) are used to control the bandwidth of the excimer lasers. The laser development will be supported by modeling calculations and experimental (plasmadiagnostic) measurements.

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  • Research Project