Preparation of Hydrogel‐Silica Composite Films by Electrochemically Triggered Deposition

Abstract

Summary:The electrochemical formation of hybrid films containing both a polymer and porous silica was performed in two different ways. In both cases, the deposition of the inorganic oxide was triggered by an electrochemical pH modulation in front of an electrode. Hydrolysis and condensation of the alkoxysilane precursors in the pH gradient yielded silica structures on the electrode surface. In the first route, an electrode was employed which had been previously coated with a polymer hydrogel. In this case, the silica readily precipitated into the hydrogel, forming rigid structures with thicknesses in the range of 100 nm. A second approach makes use of the deposition of an alkoxyvinylsilane precursor. Subsequent electrochemically induced polymerization of a polymer hydrogel inside these films is possible, but yields lower thicknesses than route I. This is explained by a blocking of the electrode by the vinylfunctionalized silica film.