25 examples of research with impact: The endless potential of plasma

As the FNR marks 25 years since its creation, we highlight 25 examples of FNR-supported research with impact. Over the past 17 years, the Plasma Process Engineering Group, headed by Patrick Choquet until his upcoming retirement, has developed solutions for anything from dental implants, protecting steel in marine environments, antibacterial surfaces as well as several types of innovative coatings.

Plasma is the result of some ingredients and a reaction on the atomic level: Plasma can be produced in the lab by heating a gas to an extremely high temperature. This causes such hard collisions between its atoms and molecules that electrons are ripped free, providing the electrons and ions needed to make plasma.

The Plasma Process Engineering Group

The Plasma Process Engineering group at LIST, headed by Patrick Choquet from its creation until his 2024 retirement, develops fundamental and technological expertise in the area of process engineering for advanced surfaces coatings. The group focuses on its recognised expertise in Research and Development of both thermal and plasma surface modification for the synthesis of functional polymer thin films, functional inorganic coatings, or functional/smart surfaces. The FNR has supported many of their research projects over the years. The team has around 10 – 15 running research projects at all times, many of them made possible by FNR funding.

New coatings designed

Over the past 17 years, the researchers in the Plasma Processing Group have developed various solutions to enhance the performance of different manufacturing products. The team has, for example, tackled the issue of steel corrosion in marine environments and created eco-friendly alternatives to replace chemical methods used for bonding polymer fibers with rubber or resin with thin copper foil.

The group has also successfully designed new coatings that are both hard and resistant to high temperatures for cutting tools. Innovations also include solutions to create antibacterial surfaces, surfaces that break down pollutants using light, fire-resistant surfaces, and temperature-responsive surfaces useful for cell culture, among others.

Group members have benefitted, for example, from the FNR’s INTER Mobility programme. It enabled Nicolas Boscher to conduct a 1 year research stay at MIT in Boston. Boscher later became the first researcher at LIST to secure a prestigious grant from the European Research Council (ERC), work building on previous findings of the FNR supported project POLYMORPH.

Using plasma to deposit materials on surfaces

The team also used chemical molecules with macrocycles called Porphyrins to create new organic surfaces. This involves a technique called “Chemical Vapor Deposition”, where the material to be coated is placed inside a dedicated machine, some of which have been designed in Luxembourg in the Plasma and Process Engineering Group. The ions of the plasma – usually nitrogen or argon gas – then splinter the matter and deposit it on the material to be covered. It is often used for hard coatings, making them resistant to oxidation at high temperature, for example.

“The chemical vapour deposition research activity was initially supported by the FNR in the project SURFAMINE. With the help of a collaboration with the University of Mainz, in Germany, we were able to start this new area of research in the laboratory. Then, my colleague Dr Nicolas Boscher had the opportunity to prepare an ERC grant on this topic and succeeded.”

Stainless steel samples covered in different titanium-based coatings, which the researchers mainly use to put on cutting tools or drills to increase toughness and durability. Depending on the composition, the researchers get different properties with resistance to different stressors, such as friction or saltwater.

Titanium
dioxide, one of the materials deposited with the help of plasma

Antibacteral coating for better dental implants

The scientists in the Plasma Process Engineering Group have built, or improved, a large part of the machines in the lab.

One of them is a robot arm with a plasma torch – the Plasma Robot. It makes it possible to coat complex objects with a lot of detail – such as dental implants, screws inserted into the bone structure. The researchers are for example using the Plasma Robot to give the dental implants with an antibacterial coating, with the aim of improve the dental bone structure and avoid any rejection of the implant.

The work in dental implants is part of the BIOADBD, supported by an FNR INTER (internatioanl collaboration grant).

“During this project, we have developed a plasma surface treatment for dental implants to avoid peri-implantitis, inflammatory conditions affecting the soft and hard gum tissues around dental implants. This research was carried out in collaboration with two other public laboratories, the University of Liège and the University of Turin and small private companies in Europe in Belgium Symbiose-Biomaterials, in Italy Nobil-Bio and in Luxembourg Alkom-Digital.”

The progress of the project was taken to next level in the project BIOIMPACT, launced in 2023, supported by an FNR JUMP which supports advancing the development of applied research-driven and leading-edge technologies/concepts. This project was launched by Dr Roberto together with visiting researcher Dr Pascal De March. In 2024, the dental implant coating will be tested for in-vivo validation.