Properties of Siloxane Coatings Deposited in a Reel‐to‐Reel Atmospheric Pressure Plasma System

This study reports on the deposition of nanometre thick siloxane coatings on a poly(ethylene terephthalate) (PET) film using a reel‐to‐reel atmospheric pressure plasma system. Coatings were deposited in a helium/oxygen plasma, from the siloxane precursors poly(dimethylsiloxane), tetraethylorthosilicate, octamethylcyclotetrasiloxane and hexamethyldisiloxane. Through control of the processing conditions the chemistry of the deposited coatings were tailored to provide a range of hydrophilic (SiO x type) and hydrophobic [SiO(CH 3 ) x ] surfaces. The silicon‐containing coating surface energies were in the range of 28–70 mN · m −1 and these values were correlated with the surface chemistry. An increase in the hydrophilicity of the coating was found to be associated with a decrease in the concentration of methyl functional groups.