Competitive scission and cross linking in a solid polymer electrolyte exposed to gamma irradiation: Simulation by a fractal model

Gamma irradiation influences the microstructure of polymers that significantly affects the correlated properties of solid polymer electrolytes (SPEs). The present paper introduces a deterministic fractal model of polymer molecules and investigates the morphological changes due to gamma irradiation in SPE. The computer aided simulation is primarily based on radiation induced scission and/or cross linking of polymer molecules. The drift velocity of conducting ion which is proportional to conductivity, is calculated considering two competing effects, viz. trapping effect of ions diffusing inside a branched fractal molecule and the motion assisted by segmental motion of the polymer itself. Variations in ionic conductivity, molecular weight distribution, intrinsic viscosity etc., as a function of probability of scission and/or cross linking show significant correlation with microstructural change induced by gamma radiation of variable dose. The present theoretical study enables easy understanding for correlation of associated properties exhibited upon experimental system perturbation through gamma irradiation. •The polymer system is modelled as deterministic Vicsek fractal.•Theoretical simulation carried out on the polymer system perturbed by gamma irradiation.•Simultaneous scission & cross-linking are considered as an effect of irradiation.•Ionic motion is controlled by trapping phenomena & polymer segmental motion.•Variations in conductivity & viscosity are simulated as a function of radiation dose.