The Response Characteristics of Organic Gas Using QCA Coated with Polymeric Materials

Abstract

The new system for identification of organic vapours and analysis method of mechanism between organic vapours and sensitive materials were attempted using the resonant resistance and resonant frequency of Quartz Crystal Analyzer (QCA). The resonant resistance shift means rheological changes in sensitive LB films occurred by the adsorption of organic vapours, while the resonant frequency shift represent the mass of organic vapour loaded in or on the sensitive LB films. Thus we can obtain more accurate response mechanism of organic vapour using the resonant frequency and resonant resistance diagram. The organic vapour response mighit be devided by two type; surface adsorption and penetration into sensitive material. The interface between inner side and surface of sensitive LB films is not clear yet. Organic vapours had different positions in the Frequency-Resistance (F-R) diagram as to the kinds and concentrations. Thus F-R diagram can be applied to the development of one-channel gas sensing system using the Quartz Crystal Analyzer.