Static Secondary Ion Mass Spectrometry and X-Ray Photoelectron Spectroscopy of Deuterium- and Methyl-Substituted Polystyrene

Abstract

Denteration in polystyrene (PS) and the differences between PS, poly(4-methyl styrene) (P4MS), and poly( α-methyl styrene) (PAMS) were examined with static secondary ion mass spectrometry (SIMS) and x-ray photoelectron spectroscopy (XPS). Only the effects of methyl substitution could be distinguished by XPS on the basis of the valence band spectra. However, it was demonstrated that both deuterium and methyl substitution effects could be clearly distinguished by static SIMS. Additionally, the effect of these substitutions could be explained in a manner analogous to that used for electron impact (EI) mass spectrometry. By the use of deuterium-labeled polymers, H scrambling was observed during secondary ion formation from PS. The validity of previously postulated secondary ion structures was confirmed on the basis of the fragmentation patterns of both the deuterium and methyl-substituted PS.