Metal Ion Incorporation in the Conducting Polymer Electrode Matrix Using an \u27Active\u27 Metal Substrate

The incorporation of free transition metal cations (potential redox catalyst centers) into conducting organic films by electrodeposition is relatively rare due to the repulsive nature of the positive cation radicals of the polymer itself during polymerization. This paper shows that such metal cations can be trapped in the polymer matrix as it is being electrodeposited on a metalsubstrate electrode, which itself simultaneously electro-oxidizes (corrodes).The electropolymerization of 3-methylthiophene on Mo(0), Ni(0) and Fe(0) substrate electrodes (\u27active electrodes\u27) is reported. SEM, EDXRF, and XPS were used to demonstrate the amount of metal cations in and/or on thepolymer matrix and to determine the valence states. The rates of diffusion ofthe incorporated metal ions into an LiClO4 electrolyte solution were also studied. The presence of trace amounts of all three metal cations were sufficient to destroy the electroactivity of the polymer film electrodes for theoxidation of catechol. (C) 1997 Elsevier Science S.A