XPS study of radiation-induced modification of poly(butene-1-sulfone): Dependence on the energy deposition mechanism

The chemical response to Ar atom, electron and photon irradiation of a model aliphatic polysulfone, poly(butene-1-sulfone) (PBS) has been studied by X-ray photoelectron spectroscopy. For all the irradiation conditions the radiation-induced chemistry is controlled by two competing reactions respectively involving (a) the main chain scission, through the breaking of C-S bonds, and the emission of SO2 molecules, and (b) the reduction of the -SO2- (sulfonyl) groups to S- linkages, probably trapped in a reticulated polysulfide-like phase. We have found that the rate and the relative yield of these reactions depend critically on the energy deposition mechanism. In particular, we have observed that many aspects of the radiation-induced chemistry of PBS are mainly ruled by the electronic term of the energy deposition. The collisional term decreases the efficiency of some of the electronically driven processes, by promoting the formation of a peculiar phase in which a relatively high concentration of sulfidic bonds remains stable. (C) 2000 Elsevier Science B.V. All rights reserved.