Humidity sensing using polyaniline/polyvinyl alcohol nanocomposite blend

Abstract

Studies on organic conducting polymers have gained attention in the past decade due to their simple, low cost fabrication processes, low temperature operation and ability to conform to various device shapes and geometries. This paper presents chemical oxidative synthesis of HCl doped polyaniline (PANI)/polyvinyl alcohol (PVA) nanocomposite using ammonium persulphate as oxidizing agent. PANI/PVA blends were prepared by adding 0.05mM, 0.1mM and 0.15mM concentrations of PVA into synthesized PANI in aqueous solvent. UV-Visible spectroscopy and FTIR spectroscopy were used to investigate the analytical and functional groups present in the synthesized nanocomposites. The results indicated the formation of highly conducting PANI/PVA blends. Humidity sensors were prepared by casting thin films of as-prepared nanocomposites with varying concentrations of PVA onto interdigitated electrodes over PCB. On exposure to humidity, it was observed that the electrical resistance of the fabricated sensors reduced by 60-75% for 90% humidity. It may be concluded that the addition of appropriate amount of PVA to PANI enhanced the humidity sensitivity.