METAL-ION INCORPORATION IN THE CONDUCTING POLYMER ELECTRODE MATRIX USING AN ACTIVE METAL-SUBSTRATE

The incorporation of free transition metal cations (potential redox ca talyst centers) into conducting organic films by electrodeposition is relatively rare due to the repulsive nature of the positive cation rad icals of the polymer itself during polymerization. This paper shows th at such metal cations can be trapped in the polymer matrix as it is be ing electrodeposited on a metal substrate electrode, which itself simu ltaneously electro-oxidizes (corrodes). The electropolymerization of 3 -methylthiophene on Mo(0), Ni(0) and Fe(0) substrate electrodes ('acti ve electrodes') is reported. SEM, EDXRF, and XPS were used to demonstr ate the amount of metal cations in and/or on the polymer matrix and to determine the valence states. The rates of diffusion of the incorpora ted metal ions into an LiClO4 electrolyte solution were also studied. The presence of trace amounts of all three metal cations were sufficie nt to destroy the electroactivity of the polymer film electrodes for t he oxidation of catechol. (C) 1997 Elsevier Science S.A.