THE INFLUENCE OF UNUSUAL COUNTERIONS ON THE ELECTROCHEMISTRY AND PHYSICAL-PROPERTIES OF POLYPYRROLE

A series of different counterions have been incorporated into polypyrrole electrochemically. These include toluenesulphonate (TS), pyrenesulphonate (PSA), Pyrene-1,3,6,8-tetrasulphonate (PTSA), dodecylbenzenesulphonate (DBS), 1,2-bis (decyloxycarbonyl)ethane-1-sulphonate (DOCES), octachloro-dirhenate (Re2Cl8) and tetraphenylborate (TPB). Electrochemical redox behaviour of the pyrrole monomer and the polypyrrole incorporating these different anions was investigated and is discussed. From scanning electron microscopy (SEM), it is shown that the different counterions incorporated strongly affect the morphology of the polymer films, they vary from fully dense to open structures. Chemical and physical characterization of the materials is presented and suggests that the sizes of the different counterions incorporated also influence the polymer chain structures, packings and their thermal stabilities. The pyrrole to counterion stoichiometries are very different, ranging from 1 to 13. In most cases, the redox potential of the polymer can be related to the size of the counterion but the electrical conductivity, which ranges from 2×10-3 to 50 Scm-1, is not simply related to the counterion but is dependent on both chain structure and bulk morphology. © 1990 Chapman and Hall Ltd.