Deposition of organosilicon coatings from trimethylsilyl acetate and oxygen gases in capacitively coupled RF glow discharge

The aim of the present work was to prepare SiOxCyHz coatings in capacitively-coupled RF glow discharge from gaseous mixture of trimethylsilyl acetate (TMSAc) monomer and oxygen. The properties of deposited coatings have been investigated using several characterization methods. The presented study proves that properties of TMSAc-based thin films are significantly dependent on the monomer ratio in TMSAc/O-2 mixture which varied from 25.0% to 92.3%. Using a low TMSAc ratio (high content of oxygen gas) resulted in organosilicon materials similar to SiO2 in terms of chemical composition and mechanical properties. Increasing the fraction of TMSAc in gaseous mixture led to the formation of more organic polymeric structures enriched with carbon atoms bonded in CH x chains. Values of Martens hardness decreased from 3.97 to 0.76 GPa with increasing TMSAc fraction from 25.0% to 92.3%. The degree of hydrophobicity of prepared coatings evolved in accordance with observed structural changes corresponding to applied monomer ratios. The water contact angle gradually increased from 75.0 degrees to 95.3 degrees with increasing TMSAc fraction. The prepared TMSAc plasma polymers became more hydrophobic with more intensive integration of hydrocarbon species into the surface structure.