Detection of hydrogen sulfide: the role of fatty acid salt Langmuir-Blodgett films

Different fatty acid Salt (cadmium arachidate, lead arachidate, zinc arachi date etc.) Langmuir-Blodgett (LB) films were deposited onto piezoelectric q uartz crystal microbalance (QCM) electrode surfaces. The reaction kinetics of the LB films with hydrogen sulfide (H2S) molecules was monitored using n anogravimetric technique. The exposure of H2S gas into the LB films showed a East response that was manifested by a dramatic change in the frequency o f QCM at the initial stage. The influences of film deposition method, film thickness, type of metal ion, concentration and pressure of H2S gas upon ga s sensing properties were investigated. The fast and irreversible reaction of LB films with H2S gas suggests that fatty acid salt LB films can be a po tential candidate for gas sensing applications. (C) 2000 Elsevier Science B .V. All rights reserved.