Radiation effects of keV-MeV ion irradiated PVDF

Polyvinilydene fluoride (PVDF) is a fluoropolymer very useful in the manufacture of synthetic bio-membranes through processes of ion energy deposition. Semicrystalline PVDF, irradiated with different ions in the range 100 keV-100 MeV, exhibits a strong change of crystalline structure, as detected by X-ray diffraction measurements as well as calorimetric analysis. PVDF ion irradiation produces a strong molecular emission for masses 2, 19 and 20, as detected “in situ” by a mass quadrupole spectrometer. At low ion doses, in the range 100–300 kGy, the diffraction analyses show a structure reordering along the (020) atomic plane. At high ion doses, the fluoropolymer shows a degradation of the crystalline structure which consists in radiation damage, reduction of hydrogen and fluorine concentration and formation of carbon reticulation. A phenomenological model, based on the ion track picture, is proposed to explain the experimental data.