SURFACE STUDIES OF POLY(ORGANOPHOSPHAZENES) CONTAINING DIMETHYLSILOXANE GRAFTS

Poly(organophosphazenes) containing dimethylsiloxane grafts were synth esized by carrying out hydrosilylation reactions on polymer precursors that contained unsaturated side groups. The surface properties of the siloxane-containing polymers were studied by contact-angle measuremen ts and X-ray photoelectron spectroscopy. A cosubstituent poly(organoph osphazene) containing both trifluoroethoxy side groups and grafted dim ethylsiloxane side groups was found to have a surface rich in -CF3 gro ups. A poly(organophosphazene) with siloxane grafts but phenoxy groups as the second substituent showed surface enrichment of the siloxane s pecies. Surface-specific hydrosilylation reactions were detected betwe en an allyl-functional polymer and heptamethyltrisiloxane dissolved in nonsolvents for the polymer. Polymer films showed the presence of sil icon to depths of 25-60 mu m as measured by energy-dispersive X-ray sp ectroscopy.