Static ToF-SIMS analysis of plasma chemically deposited ethylene/allyl alcohol co-polymer films

Abstract

A plasma co-polymerization of ethylene as a “chain extending” monomer and allyl alcohol as a carrier monomer for hydroxyl groups was studied. The composition of the feed gas was systematically varied and the plasma co-polymers were analyzed in terms of their relative concentrations of OH functional groups by static Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) immediately after their preparation without any air contact, i.e., under so called “in situ” conditions. The relative OH group concentration involved in the –CH 2–OH groups was derived from the normalized yields of the CH 3O + secondary fragment ion. The density of functional groups in the plasma co-polymers was found to vary non-linearly with respect to the mole percentage of the monomers in the feed gas. Co-polymerization phenomena, i.e. chemical interactions and recombination reactions taking place between monomer molecules in the plasma and/or during the deposition process, become evident in ToF-SIMS spectra.