Composition-property relationships for poly((3-methylthiophene)-co-(1-methyl-3-(pyrrol-1-ylmethyl)-pyridinium)) electronically conducting ionomer films

Abstract

3-Methylthiophene and 1-methyl-3-(pyrrol-1-ylmethyl)pyridinium perchlorate have been copolymerized electrochemically to form thin electronically conducting ionomer films on electrodes. The morphology and thickness of the films were investigated by scanning electron microscopy and the compositions were determined using an electron microprobe. The electrochemistry of the copolymers is similar to that of the two homopolymers and is very fast. In-situ electronic conductivities, measured by dual-electrode voltammetry and impedance spectroscopy, increase with increasing 3-methylthiophene content. The copolymers exhibit very high ionic conductivities in both their reduced and oxidized forms. Ionic conductivities increase with increasing 3-methylthiophene content owing to increasing porosity. An oxidized equimolar copolymer had an ionic conductivity of 6 × 10 −4 Ω −1 cm −1 in acetonitrile containing 0.1 M Et 4NClO 4.