Non-electroactive electrode coatings formed by electrochemical polymerization

Platinum and gold electrodes are coated with thin, adherent polymer layers by the oxidation of divinylbenzene, 4-vinylpyridine, or phenol, and by the reduction of N-methyl-4-vinylpyridinium salts. All depositions are performed in acetonitrile electrolytes. The neutral polymer coatings derived from the first three monomers affect the cyclic voltammetry of reversible redox couples by controlling the rate of diffusion to the electrode surface. The neutral form of a redox couple penetrates the coating more rapidly than the charged form. Extreme negative potentials cause a marked swelling of the coatings; the swelling is partially reversible. An anomalous prewave appears for ferrocene oxidation. The cationic polymer coating derived from N-methyl-4-vinylpyridinium traps ferrocyanide electrostatically.