Corrosion protection of mild steel electrode by electrochemical polymerization of acrylamide

Polyacrylamide (PAA) film was electrosynthesized on mild steel by cyclic voltammetry using a Ce(IV) sa lt – oxalic acid initiator system. Polymerization was initiated by a free radical that is formed by fast reaction of oxalic acid and Ce(IV). The electrolysis of the sol ution results in regeneration of Ce(IV), which can oxidize the oxalic acid and produce radicals. The effect of temperature on the yield of the electroinitiated polymerization was studied. The potential sweep rat e was changed to achieve polymer films with differe nt levels of thickness. The capacity of the PAA film t o protect mild steel from corrosion in an 1 M NaCl aqueous solution was investigated by potentiodynamic polari zation curves and electrochemical impedance spectroscopy (EIS). The structure of the PAA film on mild steel was investigated by physicochemical me thods such as elemental analysis of C, H and N by a FTIR spectrometer. The results of the studies reveal tha t the corrosion resistance of PAA-coated mild steel is si gnificantly higher and the corrosion rate considerably lower than for uncoated steel. PAA films formed wit h lower sweep rates exhibited a larger positive shi ft of the corrosion potential and greater charge transfer res i tance, reflecting as higher inhibitors for corrosion of mild steel.