Investigation of gas sensing properties of chemically synthesized polymer metal oxide nanocomposites

Abstract

The present thesis deals with the study of gas sensing properties of polyaniline (PANI), titanium oxide (TiO2) and their nanocomposites i.e. PANI/TiO2 having different wt % (2 wt % to 15 wt %) of metal oxide nanoparticles incorporated in polymer matrix PANI ranging from using in-situ oxidative polymerization method. After gaining complete in-sight into their structural and spectroscopic properties, these materials were employed in the gas sensing applications. The ohmic behaviour of all the samples was studying and conductivity studies were also performed by using two probe method. Firstly PANI sensing film was employed for studying the sensing response of different organic vapours under study namely: methanol, ethanol, propanol, benzene and diethyl ether. Different parameters such as sensing response, response time recovery time etc, were also evaluated for gaining complete in-sight into the performance of PANI as a sensor. In the next step TiO2 was employed for the sensing studies of same set of target vapors under similar experimental conditions. The problems encountered while employing PANI and TiO2 as a sensing film alone were resolved by fabrication of PANI/TiO2 nanocomposites by adding different wt % (2 wt % to 15 wt %) of TiO2 nanoparticles in PANI matrix. From the sensing studies, it could be concluded that PANI/TiO2 (10 wt %) sensing film has shown remarkable sensing response towards the target vapours with very fast response and very efficient recovery time values and could be successfully employed as a sensing material for low level sensing of organic vapors. newline