50 MeV lithium ion beam irradiation effects in poly vinylidene fluoride (PVDF) polymer

Irradiation effects of 50 MeV 7Li+3 ion beam induced in bulk PVDF polymer have been studied with respect to their optical, chemical, structural and electrical behaviour by using UV visible, FT-IR spectroscopy, XRD technique and electrical frequency response using LCR bridge. The ion fluences ranging from 1.27 x 1011 to 2.15 x 1013 ions cm-2 have been used to study dose effects of irradiation in PVDF. The recorded UV-visible spectra clearly shows five characteristic peaks at 315, 325, 360, 425 and 600. Due to irradiation, the optical absorption initially decreases but then increases with higher fluences. In the FT-IR spectra, no appreciable change has been observed after irradiation, indicating that this polymer is chemically stable. There is exponential increase in admittance with log of frequently but the effect of irradiation is not quite appreciable. The value of tan δ and relaxation frequency are changed appreciably due to irradiation. The diffraction pattern of PVDF indicates that this polymer is in semi-crystalline form; a decrease in the crystallinity and crystallite size has been observed due to irradiation. (author)