Effect of Plasma Exposure on the Chemistry and Morphology of Aerosol‐Assisted, Plasma‐Deposited Coatings

This study reports on the effect on the morphology and chemistry of atmospheric pressure plasma deposited nm‐thick coatings (21 ± 3 nm) as the level of exposure to the plasma is systematically altered. Coatings were deposited by directly injecting hexamethyldisiloxane, polydimethylsiloxane or tetramethyldisiloxane liquid precursors through a nebulizer into a helium/oxygen atmospheric pressure plasma. An increase in the level of the precursor was found to be associated with a decrease in the concentration of methyl functional groups in the coating and to an increase of the SiO crosslinking, as demonstrated using surface energy and XPS analysis. This resulted in an increase in the coating refractive index, and in a reduction of the number of surface particulates, as well as of surface roughness. magnified image