XPS STUDY OF ION-INDUCED CHANGES ON THE SURFACE OF AN ORGANOSILICON MODEL POLYMER

Changes in composition and bonding induced by bombardment with argon or nitrogen ions in a commercial poly-methyl-phenyl-cyanopropyl-siloxane fluid were examined by XPS. The actual surface composition depended on the ion energy, the etch time and the nature of the gas applied. It was found that phenyl groups were damaged seriously, reaction of the cyano groups took place with the formation of minus C equals N minus type bonds and the polymer degraded with elimination of fragments containing mostly C at the first stage and mainly O and Si at advanced stages. In addition nitrogen was found to build into the polymer surface when bombarding by nitrogen ions. Irreversible changes in the spectra of the fluid polymer were regarded as a sign of crosslinking.