Ion transport in thin polypyrrole films

Abstract

Fundamental and applied aspects of ion transport in polypyrrole films are investigated. In this context, three objectives have been accomplished: i) Composites of polypyrrole and a porous host membrane have been prepared which possess superior mechanical properties to the homogeneous polymer, but which retain its desirable electrochemical characteristics. ii) Two new electrochemical methods for quantitating ion transport in polypyrrole films are demonstrated. The small amplitude nature of both experiments minimizes the perturbation of the polymer redox state. These techniques circumvent many of the problems associated with the determination of diffusion coefficients in conducting polymers with conventional large amplitude electrochemical methods. iii) A technique for synthesizing polypyrrole films possessing a well defined "fibrillar-microporous" (F/MP) morphology which facilitates ion transport is developed. Controlled morphology films prepared using this new method are electrochemically characterized. The generality of this electrochemical method for preparing highly structured surfaces is demonstrated by depositing platinum structures with the same well-defined F/MP geometry. A modification of this procedure is used to prepare ultramicroelectrode ensembles (UME). UME's have electroanalytical applications since the signal-to-noise ratios for such electrodes are enhanced relative to those obtained at electrodes with conventional dimensions.