Effect of electron irradiation on optical, thermal and electrical properties of LiClO4/PVA polymer composite

The LiClO4/PVA Polymer films were irradiated with energetic electrons and are characterized using various experimental techniques. The observed FTIR results in terms of band intensity, shift in the band position and appearance of new peak after electron irradiation indicate that the irradiation produces free radicals, which led to chain scission and cross-linking within the polymer network. The optical properties were studied using UV-Vis spectra and the observed absorption peaks are assigned to π-π* and n-π* transition. Using optical absorption spectra, the optical parameters like maximum molar extinction coefficient, transition dipole moment, dipole strength, dipole length, oscillator strength and optical energy band gap are determined. The variations in optical parameters are attributed to the variations in the carbonaceous clusters/charge transfer complex (CTC) which are created during the electron irradiation. The DSC study confirms the variation in thermal properties of polymer. The presences of these CTCs within the composite film also affect the electrical conductivity of the polymer composite and the highest electrical conductivity (2.7598×10-4 S/cm) was obtained for 300 kGy dose. All these variations in structure and electrical properties are understood by invoking the cross-linking and chain scission process occur within the composite upon irradiation. This study shows that the electron irradiation is one of the best method to modify the structure and other properties of a polymer composite.