Ammonia sensing characteristics of thin film based on polyelectrolyte templated polyaniline

A novel conductive polyaniline is synthesized using poly(4-styrenesulfonate-co-maleic acid) as counter ion and template. The resistance of this electroactive polymer increases in the presence of gases such as ammonia. This transducing property is exploited and spin-cast film of this material on glass substrate is established as ammonia gas sensor module, for gas concentrations in the range 5-250 ppm. In this range, the response and recovery times are typically 50-1000 s. The resistance response (R/R-0) at short time scales of about 150 s, is shown to vary linearly with the ammonia concentration. (c) 2004 Elsevier B.V. All rights reserved.