Role of novel microstructure of polyaniline-CSA thin film in ammonia sensing at room temperature

A polyaniline (Pani) thin film doped with camphorsulfonic acid (CSA) has been deposited using spin coating technique on a glass substrate. Polyaniline is chemically synthesized by an oxidation method at ∼0 °C. Sensing experiments are performed on the Pani-CSA thin film with the injection of 50, 100, 150 and 200 ppm level NH3 at room temperature. The change in resistance, based on the modification of doping level, occurs due to redox interaction of the analyte. Response and recovery times are found to be ∼1 s and ∼7 min, respectively. The hexagonal structure seen in the scanning electron micrograph is helpful in making the sensor response fast.