Crystallinity and Stretch Orientation in Polyaniline Camphor-Sulphonic Acid Films

Abstract

This chapter discusses crystallinity and stretch orientation in polyaniline (PANI) camphor-sulfonic acid (CSA) films. The chapter describes the results of a range of measurements on PANI:CSA films aimed at probing the role that CSA and m-cresol play in both microstructure and electrical transport and to understand why only this combination gives such desirable physical properties. Experiments on the PANI:CSA system indicate that by careful sample preparation, very consistent results can be achieved. By varying the percentage of CSA in films, some insights into the role played by the CSA can be gained. X-ray data reveal that sample crystallinity depends on the doping level. The onset of a metallic conductivity component was observed at ca. 30% doping. This became more dominant on increasing the doping level to 60%. At this CSA doping level, the samples remained metallic to 135 K. A good correlation was observed between crystallinity and metallic conductivity. On the removal of m-cresol, changes were observed in the crystalline phase, especially the loss of the 20 A feature. Such pumped samples are much less metallic and have lower overall conductivity. Stretch orientation further enhances the physical properties of the films, thereby giving room-temperature conductivities up to ca. 960 S cm-1 at 120% elongation.