In order to facilitate the implementation of (nano)particles into commercial products, important challenges need to be tackled with regard to the processability of these particulate materials (e.g. dispersibility, flowability, interfacial adhesion, etc.). Due to the high specific surface area of (nano)particles, surface modification is often a crucial step to tune the interaction between the particles and their environment, without changing the bulk properties.
VITO has developed an atmospheric plasma process for surface treatment of polymeric and inorganic particles. Atmospheric plasma is a cold technology allowing the treatment of heat-sensitive materials. The functionalization is done in the gas phase or with the addition of a small amount of precursor, limiting the use of hazardous solvents.
Treatment of powders via plasma technology can tune several properties: by grafting the appropriate chemical groups or depositing a very thin coating onto the particle surface, it is possible to tailor the wettability of the particles or improve their flow behavior. Surface functionalization can enhance the compatibility between the particles and their environment and this is crucial in the production of plastics, composites, coatings, cosmetic and pharmaceutical products, etc.
A powder downflow reactor is available for treatment of both organic and inorganic powders in an atmospheric DBD (dielectric barrier discharge) plasma. The process is based on dry injection of the powder in a gas flow and gaseous and/or liquid precursors can be added to apply specific functional groups. Powder volumes up to 500g can be treated per batch.