Electropolymerization of 2-methacryloyloxy(ethyl) acetoacetate on aluminum using a novel initiation method

Abstract

Electropolymerization has been used as a method to form polymers on graphite fibers and metals. Most of the previous studies have involved either the use of sulfuric acid as an initiator or direct reduction or oxidation of monomers to form the polymers. In this article, α-bromoisobutyronitrile (BrIBN) was used as a new electrochemical initiator to form polymer coatings on an aluminum cathode. The reduction of BrIBN on a glassy carbon electrode was examined using cyclic voltammetery. It was found that BrIBN could be reduced to isobutyronitrile radicals at potentials below the reduction potential of water. The reduction behavior of BrIBN was found to be similar in aqueous, semiaqueous, and nonaqueous solutions. 2-Methacryloyloxy(ethyl) acetoacetate was then electropolymerized on aluminum using the BrIBN as the initiator and lithium perchlorate as a supporting electrolyte. Defect-free coatings were formed at half-cell potentials of less than −1.20 V. The effect of various process variables on the polymerization kinetics under potentiostatic conditions is reported. The coating thickness increased with polymerization time, monomer concentration, and initiator concentration. A strong dependence of thickness on monomer concentration was observed. As expected, there was weak dependence on the initiator concentration. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1665–1675, 1999