Protective coatings deposited on polycarbonates by pulsed dielectric barrier discharge

Organo-silicon layers were deposited on polycarbonates (PC) substrates from the gas phase by using pulsed dielectric barrier discharge. Very short (~ 20 ns) pulses of high power discharge (-0.4 MW) were applied. The process was carried out under atmospheric pressure in a helium-oxygen plasma. Tetraethoxysilane (TEOS) vapours were used as a source of silicon. The surface morphology, composition and thickness of the layers were studied by means of AFM/TM, FTIR and SEM. The organo-silicon layers were found to be transparent, smooth and uniform over the whole substrate surface. The amplitude of the deviations from surface uniformity did not exceed 30 nm. The thickness of the deposited layers was of the order of ~2 |j.m.