Electropolymerised acrylic coatings for polymer-metal adhesion enhancement

Electrochemical polymerisation (ECP) of acrylic monomers produces thin coatings on metal substrates and is a potentially useful method for forming adhesion promoting tie-layers at a polymer-metal interface. Uniform, passive films of poly (methyl methacrylate) and poly (glycidyl acrylate) have been formed via a cathodic free radical mechanism on stainless steel electrodes from aqueous electrolytes. The thickness of these films was found to increase with electrolysis time and the passive nature has been demonstrated by cyclic voltammetry studies. Adhesion tests were performed to compare the adhesion strength and failure mechanisms of various adhesives to coated and uncoated stainless steel substrates. The results indicate that ECP tie-layers can significantly increase the adhesive bond strength and alter the failure mechanisms observed. Electropolymerised acrylic coatings on metal substrates are thus seen as a promising approach for pretreatment of metals for adhesion enhancement.