EFFECTS OF DAMAGE DURING THE SIMS ANALYSIS OF POLY(VINYL CHLORIDE) AND POLY(METHYL METHACRYLATE)

The spectral time dependence of poly(vinyl chloride), PVC, has been investigated for bombardment by argon ions and atoms. Some comparative observations are made for poly(methyl methacrylate). The spectrum of PVC is found to change with dose. The characteristic peaks in the secondary ion mass spectrum of the virgin material decline rapidly in intensity during ion bombardment. A range of different peaks, thought to have polycyclic aromatic structures, become prominent at high doses. The rate of appearance of these ions is found to be retarded by the use of uncharged primary particles. Comparative studies suggest that the behaviour of PMMA is similar and that for PMMA, degradation rates may also be reduced by employing neutral primary particles. It is concluded that there are major advantages offered to the surface analyst by the application of atom bombardment as opposed to ion bombardment.