Development of a polyaniline-based optical ammonia sensor

A polyaniline film was deposited on polyethylene surface by chemical oxidation of aniline monomer at room temperature. The ammonia gas sensing capabilities of the polyaniline film were studied using absorption spectroscopy method. A significant change was observed in the absorption spectra of the film after it was exposed to ammonia gas. The optical ammonia gas sensors have a response time of less than 15 s and a fast regeneration time of less than 2 min at room temperature. The sensors have a detection limit of 1 ppm (v/v) for ammonia, with a linear dynamic range from 180 to 18 000 ppm.