Electric Resistance Changes of Polypyrrole Composite Films Exposed to Methanol Vapor

Abstract

Polypyrrole composite films were prepared by chemical oxidative polymerization of pyrrole using poly (vinyl alcohol) (PVA) or poly (vinyl acetate) (PVAc) as a matrix polymer. These films were applied to measure their resistance changes by exposing to methanol vapor. It was found that the surface morphologies of composite films vary with the matrix polymer. On exposure to methanol vapor, the PPy-PVA film exhibited an increase in its resistance, similar to that of a p-type semiconductor. On the contrary, PPy-PVAc decreased in filmresistance. The results indicate that the matrix polymer plays an important role for defining the responses of film resistance.