Ammonia sensitivity of polyaniline films via emulsion polymerization

The sensitivity of polyaniline (PANI) films to ammonia has been investigated. The PANI, soluble in several organic solvents, was prepared by emulsion polymerization. These PANI films display high sensitivity, wide range of measured concentrations and high stability. The concentration, response and temperature characteristics of the samples were also studied. It is found that the resistance of the sample increases with the increasing ammonia concentration, but decreases with the increasing temperature; the relative resistance of the film varies from 1.28 to 23.6 for ammonia concentration ranging from 10 to 1000 ppm; the sensitivity of the PANI films remains constant for a period of 80 days in ambient environment; and the response time of the film is less than 2 min.