Preparation and characterization of pure and KBr doped polymer blend (PVC/PEO) electrolyte thin films

Abstract

A potassium ion conducting polymer blend electrolyte based on polyvinyl chloride (PVC) and polyethylene oxide (PEO) complexed with KBr was prepared using solution cast technique. The structural properties of these electrolyte films were examined by XRD studies. The XRD data revealed that the amorphous domains of polymer blend matrix increased with increase of KBr salt concentration. The complexation of the salt with the polymer blend was confirmed by FT-IR studies. Electrical conductivity of the films was measured with impedance analyzer in the frequency range of 100Hz to 1MHz and in the temperature range of 303–363K. It was observed that the magnitude of conductivity increased with the increase in the salt concentration as well as the temperature. UV–VIS absorption spectra in wavelength region of 200–600nm were used to evaluate the optical properties like direct band gap, indirect band gap and absorption edge. The optical band gaps decreased with increasing of K+ ion concentration. This suggests that, KBr is a good dopant to improve the electrical properties of PVC+PEO polymer blend electrolytes. Studies on the electrical and optical properties of polymer blend electrolyte have attracted much attention in view of their application in electronic and optical devices like electro-chromic display devices, fuel cells, gas sensors and solid state batteries. The thermal properties of these films were investigated with differential scanning calorimetry (DSC). The variation in film morphology is examined by scanning electron microscopy examination (SEM).