Development of Room Temperature Operating NH3 Gas Sensor Based on Free Standing PPy-PVA Composite Films

In the present investigation, room temperature operating ammonia (NH3) gas sensor based on free-standing Polypyrrole- Polyvinyl alcohol (PPy-PVA) composite films has been fabricated. The PPy-PVA composite films were synthesized by an in situ chemical polymerization of Pyrrole in the presence of PVA. The synthesized films were characterized by Scanning Electron Microscopy (SEM), Fourier Transforms Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD). The DC electrical conductivity () of the composite films has been investigated by two probe method and was found to be 2.1610-3 S/cm at room temperature. Ammonia gas sensing behaviour of films was studied. Gas sensing tests demonstrated that the composite films exhibited a fast response, rapid recovery and high sensitivity at room temperature with a detection of low concentration (25 to 300 ppm) of ammonia gas. This work demonstrates the potential of using PPy-PVA composite films as sensing material in the fabrication of room temperature operating ammonia sensor.