Surface functionalization with oxometalates entrapped in polymeric matrices: Part I. New and remarkably stable poly(4-vinylpyridine) based redox coatings

Abstract

Entrapment of oxometalates in poly(4-vinylpyridine)(PVP) matrices on electrode surfaces results in new materials which show remarkable stability. The system is described mainly with [SiW 12O 40] 4−/PVP in acid media. Incorporation of the heteropolyanion (HPA) in the polymer is obtained readily but the cyclic voltammogram of the assembly shows its maximum peak current intensity after variable stabilization periods depending on the anions in the supporting electrolyte. The stabilization to this maximum value is fastest in the presence of Cl − or CF 3COO −. Other anions like ClO − 4 and SO 2− 4 behave differently, but several procedures have been devised to prepare stable and reproducible electrodes. Solvent effects have also been studied. It appears that HPAs included in PVP films can serve as probes to follow the dynamic behaviour of this polymer in several supporting electrolytes up to the stabilization of the electrochemical response of the electrodes. The [SiW 12O 40] 4−/PVP assembly has been shown to be stable, which makes it very attractive for theoretical studies as well as practical purposes. An attempt is made to clarify several factors that affect the electrochemical responses of the present systems.