Oligomeric Products in Plasma=Polymerized Organosilicones

Abstract

Abstract Plasma polymers were deposited from a number of methylsilazane and methylsiloxane monomers of linear and cyclic structure. The oligomeric phase evolved from the polymers by a mild thermal treatment was analyzed using gas chromatography/mass spectrometry combined techniques. The oligomeric phase was found to be composed of the low-molecular-weight products with the weight being mostly no higher than two monomer units. The results suggested that the oligomers might be formed in the gas phase and then they diffuse to the surface of the growing polymer film. The structure of the oligomeric products indicated that their formation must proceed via the Si-N and Si-O bonds fission in silazane and siloxane monomers, respectively. An ionic nature of the primary active species involved in this process was assumed owing to the high susceptibility of these bonds toward heterolytic fission. The postulated ionic mechanism, considered to account for the formation of the observed oligomers, seems to be more reaso...