Mechanism of electropolymerisation of methyl methacrylate and glycidyl acrylate on stainless steel

An aqueous based technique for producing uniform, thin, passive films of poly(methyl methacrylate) (PMMA) and poly(glycidyl acrylate) (PGA) on stainless steel electrodes has been developed. A cathodic free radical polymerisation mechanism is proposed based upon the results of cyclic voltammetry (CV), mechanistic electro-polymerisation and gel permeation chromatography (GPC) experiments. The polymerisation yield was increased by a synergistic relationship between sulphuric acid and potassium persulphate initiators, proposed to involve the formation of long-lived radical species. Termination reactions are believed to be inhibited by the formation of co-ordination complexes between the growing polymer chain and sulphuric acid. The mechanism accounts for the broad molecular weight distribution, cross-linking and post-electrolysis polymerisation, where polymer continued to form after the current flow ceased.