| Summary: | 碩士 === 國立臺灣科技大學 === 化學工程技術研究所 === 86 === Applications of conductive composite polymer films in methanol and ethanol sensing were investigated. The sensing performance was expected to be improved by the modification of conductive polymer films. The contents of this study involved(1) the material characteristiscs of PPy and PPy/PU composite films, (2) the sensing performanece of PPy and PPy/PU films for alcohol gases, (3) the effects of temperature, air ratio and moisture content in carrier gases on the sensing performance of gas sensors and (4) the kinetic analysis of gas sensing for PPy and PPy/PU composite films.
The PU fraction in polymer films synthesized by electrochemical codeposition of PPy and PU increases with an increase in the PU loading in the solution. Hydrogen bonding in the composite films was observed from the ATR-FTIR analysis. It was found that the response and recovery time decrease with increasing the concentration of sensing gases. It was also found that their sensintivity decreases with increase the PU fraction in the films. Meanwhile, the sensintivities in air was better than those in nitrogen. The moisture made the sensors unstable and their sensitivities become worse. It showed that the stability of the PPy/PU composite filns is better than of the pure PPy films.
The sensing model was also established to study the sensing kinetics of the PPy and PPy/PU films and to illustrate the relationship of sensing performance and the kinetic models. The results indicated that the sensitivity increases with increasing the initital resistance (R0) and Km(ρ１－ρ２).
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