Effect of Temperature on Electrical Conductivity of Zinc Oxide Polyvinyl Alcohol Nanocomposites

Abstract

A set of zinc oxide (ZnO)/polyvinyl alcohol (PVA) nanocomposites were prepared by mixing presynthesized zinc oxide nanoparticles and polyvinyl alcohol (PVA) in different weight percentages with solution casting technique.Different characterization methods are carried out to determine the material properties. The effects of ZnO nanoparticles loading level on electrical properties of the nanocomposites were investigated in details. The intermolecular interactions within the polymer nanocomposites were explored by FTIR and XRD. The formation of nanocomposites and changes were investigated by SEM analysis.It showed that ZnO nanoparticles were homogeneously dispersed throughout the whole polymeric matrix. DC conductivity was measured in the temperature range 70-300K and it obeys Arrhenius relation. Activation energies were evaluated from Arrhenius plots for all compositions. The samples show a semiconductor-like behavior in regions I (300-130 K) and II (130-70K).The activation energies are smaller at lower temperature range as compared to higher temperature range. The change in conduction mechanism arises at different temperatures, which are feature of the samples. As the ratio of ZnO to polymer changes these switching positions are shifted to upper temperatures. All the composites obey the Arrhenius equation for the conductivity mechanism which confirms that the nanocomposites are thermally activated. The dc conductivity of all the samples follows a simple hoping type of charge conduction method. This is evident from Fourier Transform Infrared Spectroscopy (FTIR) studies.