PLASMA POLYMERIZATION OF SOME SILICON-CONTAINING AND TIN-CONTAINING MONOMERS

Plasma polymerization of several selected saturated and unsaturated silicon- and tin-containing monomers, such as vinyltriethoxysilane (VTES), 3-aminopropyltriethoxysilane (APTS), hexamethyldisiloxane (HMDS), hexabutyldistannoxane (HBDS) and tetraethylstannane (TES), were examined in terms of the following selected plasma operational parameters: discharge time (t), flow rate of monomer (F) and power input (W). For the initial deposition rates (DR), the following empirical equation was proposed: DR = k t(a) F-b W-c, from which the experimental values of the kinetic power factors (a,b,c and k) were calculated. The value of k calculated for VTES was the highest, indicating the high activity of the monomer in plasma in contrast to HBDS, which was about two orders of magnitude smaller. A modified Arrhenius equation was employed in the form of yield of deposition (DR/F) versus the specific energy (W/F), which showed that silicon-containing monomers are more active than their organotin analogues in the chosen plasma conditions. Plasma polymers of HMDS, TES and HBDS prepared at low conversions were highly crosslinked and their structures were similar to those of crosslinked poly(dialkylsiloxane) or poly(organostannoxane) while those of VTES and APTS were primarily linear.