Polymer-coated microelectrodes and twin electrode thin layer cells applied to electron transfer cross-reaction and permeability rates

Electropolymerized films prepared from the monomers [Ru(4-methyl-4′-vinyl-2,2′-bipyridine)₃]²⁺ and [Os(bpy)₂(4-vinylpyridine)₂]²⁺ are coated on 10-μm diameter Pt microdisk electrodes and on one (Pt) face of a twin electrode thin layer cell. These new forms of polymer-coated electrodes are applied to measurements of polymer/solution interfacial electron transfer mediation kinetics and of rates of permeation of ferrocene and ferricenium through the polymer films. The electron transfer rates agree with independently determined rates from polymer-coated rotated disk electrodes. The permeation rate of ferrocene through the poly-cationic films is about three times larger than that for ferricenium ion.