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

Different fatty acid salt (cadmium arachidate, lead arachidate, zinc arachidate etc.) Langmuir-Blodgett (LB) films were deposited onto piezolectric quartz crystal microbalance (QCM) electrode surfaces. The reaction kinetics of the LB films with hydrogen sulfide (H₂S) molecules was monitored using nanogravimetric technique. The exposure of H₂S gas into the LB films showed a fast response that was manifested by a dramatic change in the frequency of QCM at the initial stage. The influences of film deposition method, film thickness, type of metal ion, concentration and pressure of H₂S gas upon gas 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 potential candidate for gas sensing applications. (C) 2000 Elsevier Science B.V. All rights reserved.