High-frequency measurements of conducting polymers: development of a new technique for sensing volatile chemicals

The change in the AC impedance characteristics of poly-N-(2-pyridyl)pyrrole in the presence of three volatile chemicals was investigated to determine whether measurement of multifrequency parameters could be used as the basis of chemical discrimination. The volatiles were selected for their characteristic odours. Methanol has a slightly alcoholic odour; acetone a pungent odour; and ethyl acetate a fruity odour. The results demonstrate quantification of concentration and discrimination between the chemicals tested on the basis of capacitance, conductance, resistance and dissipation factor as a function of frequency. (Original abstract-amended)