DC Electrical Conductivity and Liquefied Petroleum Gas Sensing Application of Polythiophene/Zinc Oxide Nanocomposite

Abstract Despite being a versatile fuel, liquefied petroleum gas (LPG) is extremely flammable even at very low concentration of 1000 ppm. Therefore, detection of LPG below the 1000 ppm is necessary for safety point of view. Herein, we are reporting the synthesis of polythiophene (PTh) and polythiophene/zinc oxide nanocomposite (PTh/ZnO) through in-situ chemical oxidative polymerization method. The structure and morphology of as-synthesized materials were determined by various techniques such as SEM, FTIR, XRD and TEM. The stability of DC electrical conductivity of PTh and PTh/ZnO nanocomposites under an accelerated isothermal as well as cyclic ageing conditions were evaluated. Both the conductivity and stability of PTh significantly improved by incorporating a small amount of ZnO nanoparticles. We also studied LPG sensing performances of pelletized form sensors based on PTh and PTh/ZnO-3 by alternate exposure in LPG atmosphere and ambient air. The lower detection limit of PTh/ZnO-3 was found to be 600 ppm. PTh/ZnO-3 based sensor exhibited about 1.58 and 4.9 times greater sensing efficiency in terms of sensing response and reversibility as compared to the pristine PTh based sensor at 2400 ppm.