Heterogeneity of swift heavy ion grafting: an XPS study

The radiation grafting of styrene in Poly(vinylidene difluoride) was performed using swift heavy ion (E > 1 MeV/amu) and electron irradiation (8 MeV). Radiation grafting can be performed whatever the kind of ionising radiation (ions, electrons, gamma-rays) used to induce the formation of the initiating radicals. Compared to a swift heavy ion irradiation where the irradiation damage is localised in the latent tracks, irradiation with electrons or gamma-rays can be considered as homogeneous at a microscopic scale. As a consequence, the distribution of the grafted domains is different. This work presents an X-ray photoelectron spectroscopy (XPS) study of the surface of radiation grafted samples. The comparison of the two kinds of radiation grafting shows that even in grafting conditions leading to small yields (< 15%), differences are observed in the composition of the grafted surfaces: the heterogeneity is much more pronounced in the case of swift heavy ion grafting. (C) 1997 Elsevier Science B.V.