The sensing behavior to volatile organic compounds gas on polypyrrole sensor under humidity condition

Polypyrrole (PPy) powder was synthesized by chemical polymerization at 0 degrees C under atmospheric condition and its layer was prepared by dip coating method on the alumina substrate with interdigitated electrodes. The influence of relative humidity (RH 0 similar to 70%) to PPy sensor was studied. The measuring temperature was fixed at 25 degrees C. Methanol and benzene were used as target gases. Various analytic techniques were examined to observe changes in the properties of PPy sensor. The sensitivity of PPy sensor to water vapor was linearly increased with the increasing humidity. As the relative humidity increase from 0% to 70%, the sensitivities to methanol and benzene vapor were reduced, and reduction ratio of sensitivity was 94%, 92.5% at RH 70%, respectively.,