The use of adsorption method to preparation of polyaniline/ZnO nanocomposite varistor

Abstract

ZnO nanosheets were synthesized using a cost effective and simple precipitation method. Polyaniline/zinc oxide nanocomposites in various weight ratios were produced by the synthesis of polyaniline as a conducting polymer followed by adsorption of polymer chains on the ZnO nanosheets. UV–Vis spectroscopy, X-ray diffraction patterns, and SEM technique were utilized to characterize the nanocomposite structure. The polyaniline/ZnO nanocomposites prepared in various weight percent of polyaniline and ZnO nanosheets were pressed as thin disks at a pressure of 60 MPa and their usage electrical varistors were studied. The current–voltage characteristics of thin polyaniline/ZnO nanocomposites disk varistors were investigated. The results demonstrated good varistor behavior of polyaniline/ZnO nanocomposite disks so that they can be used to protect the electrical circuits from over voltages in the range of 250–550 V. The efficiency of ZnO percent on the varistors properties of polyaniline/ZnO nanocomposites disks was experimented. According to the results, the nanocomposites sample containing 99.01 wt% of ZnO showed minimum breakdown voltage (250 V) and highest nonlinear coefficient (4.28) and also the lifetime of this sample is high. From the UV–Vis spectra recorded for polyaniline/ZnO nanocomposites samples with various ZnO percent, it was found that absorption and light absorption band gap decreased by reducing ZnO content in nanocomposites samples. The band gap in the best sample is 3 eV.