Functionalization of polypyrroles with acids and β-diketones as complexing groups. Part 2: electrochemical growth of polypyrrole into hybrid zirconium oxopolymer sol–gel coatings

Abstract

New hybrid materials were prepared by a sol–gel route from zirconium propoxide and functionalized polypyrroles bearing a complexing group (carboxylic acid or β-diketone). Formation of polypyrroles in the gel deposited on an indium tin oxide (ITO) electrode was performed electrochemically in aqueous media. The optimal conditions for the preparation of stable sols were determined, as well as the deposition conditions to obtain reproducible transparent uniform coatings in which electropolymerization was possible. The xerogels as well as the composites after polymerization were analyzed with the help of optical microscopy (OM), scanning electron microscopy (SEM) and X-ray fluorescence. The electrochemical characteristics of the composites were investigated by cyclic voltammetry and their adherence evaluated. From the polymerization rate and simple assumptions, the rate constant for pyrrole polymerization inside the gels has been evaluated.