Effect of swift heavy ion irradiation on dielectrics properties of polymer composite films

Ferric oxalate was used as organometallics fillers in polyvinyl chloride (PVC) to form polymer matrix composite films at different concentration of filler. These films were irradiated with 80 MeV O6+ ions at the fluences of 1 × 1011 and 1 × 1012 ions/cm2. The radiation induced modifications in dielectric properties, microhardness, surface morphology and surface roughness of polymer composite films have been investigated at different concentration (i.e. 5%, 10% and 15%) of filler. It was observed that hardness and electrical conductivity of the films increase with the concentration of the dispersed ferric oxalate and also with the fluence. From the analysis of frequency, f, dependence of dielectric constant, ɛ, it has been found that the dielectric response in both pristine and irradiated samples obey the Universal law given by ɛ ∝ fn−1. The dielectric constant/loss is observed to change significantly due to the irradiation. This suggests that ion beam irradiation promotes (i) the metal to polymer bonding and (ii) convert the polymeric structure into hydrogen depleted carbon network. Thus irradiation makes the polymer harder and more conductive. Atomic force microscopy (AFM) shows that average roughness (Ra) of the irradiated films is lower than that of unirradiated films. Surface morphology of irradiated polymer composite films is observed to change. Scanning electron microscopy (SEM) results show that partial agglomeration of fillers in the polymer matrix.