Ionic exchange phenomena related to the redox processes of polyaniline in nonaqueous media

Polyaniline films in nonaqueous; media, mainly propylene carbonate and acet onitrile, are studied by using simultaneous potentiodynamic experiments wit h the electrochemical quartz crystal microbalance and electrochemical imped ance spectroscopy. The role of ionic transport and solvent participation du ring redox reactions is emphasized to obtain information about all chemical species involved in the process occurring in the conducting polymer film. The contribution of each species (neutral and ionic) depends on both the ch emical nature of the ionic salt and the solvent used. Quartz crystal microb alance results have shown that both cation and anion contribute to the elec troneutralization process, and the participation of solvent molecules is re lated mainly to changes in the oxidation state of the polymer matrix. As pr opylene carbonate propylene (epsilon = 66.1) is a more polar solvent than a cetonitrile (epsilon = 37.3), it produces a more pronounced swelling proces s. (C) 2000 The Electrochemical Society. S0013-4651(99)06-017-6. All rights reserved.