Cyclic voltammetric and ac impedance studies on polypyrrole(PPy)-polyaniline(PANI) bilayer films have been carried out in aqueous medium. The bilayers were prepared by electrochemical polymerization of the corresponding monomers at a platinum electrode in 1M HCI solution. Cyclic voltammograms of the bilayers show additive properties of the individual polymers. The ac impedance studies of the bilayers show that when PPy is the outer layer oxidation of the inner PANI layer is mediated. The largest difference between the impedance plots of the PPy/PANI and PANI/PPy bilayers is observed at 0 V where PPy already is in its conducting state but PANI first starts to become oxidized.
- ac impedance