Effect of dopant concentration on polyaniline/poly(4-styrene sulfonic acid) composite for ammonia gas detection

Polyaniline (PANI)/poly(4-styrene sulfonic acid) (PSS) has been prepared for various molar ratios of hydrochloric acid (HCl) (1, 2, 3 and 4 M, respectively) through in situ chemical polymerization method. The reaction temperature was 25 degrees C for 3 h. Fourier transform infrared spectroscopy spectrum confirms the attachment of the structure to functional groups. The intensity of PANI is increased with increasing HCl concentration. Scanning electron microscopic graphs reveal the irregular morphology. The complex impedance of the PANI/PSS shows two distinguished semicircles and the diameter of the arcs decreased with an increase in ammonia concentration at room temperature. The sensitivity of the sensor increased with time, and the maximum sensitivity is 7.4 at 3 M of HCl for 500 ppm. The results are discussed and reported.