Ghent University – Faculty of Engineering – Department of Applied Physics – Research Unit Plasma Technology (RUPT) – Gent – Belgium

Nathalie De Geyter, Rino Morent and Christophe Leys

Low temperature plasma treatment by means of dielectric barrier discharges (DBDs) constitutes an emerging technology for polymer film treatment. DBD systems have been developed and optimised for the sterilization and activation of surfaces before printing, gluing or top-coating. However, in recent years, laboratory and semi-industrial scale experiments have demonstrated the interesting capabilities of this technology for in-situ coating deposition. This can be done by injection of gaseous or vaporized chemical precursors in the plasma discharge. Unlike low pressure plasma deposition, which generally targets metal oxide or nitride coatings, a DBD is most suited for deposition of organic and hybrid organic-inorganic coatings.

Until recently, the variety of coating precursors used in DBD deposition was limited to gaseous chemicals and liquid precursors with a high vapour pressure and/or high thermal stability which considerably limited the coating capabilities. Furthermore, deposition rates are in most cases too low to meet the requirements for in-line production. The use of nano-sized aerosols enables to overcome the latter limitations. It allows making use of the full variety of chemical compounds available today and to drastically increase the deposition rates. The presented work describes the deposition of hydrophobic coatings by injection of a siloxane-based precursor (hexamethyldisiloxane) to the plasma as aerosol particles formed by atomisation