Potentiodynamic deposition of poly (o-anisidine-co-metanilic acid) on mild steel and its application as corrosion inhibitor

For the first time, poly (o-anisidine-co-metanilic acid) (PASM) was deposited on mild steel substrate by electrochemical polymerization of o-anisidine and metanilic acid monomers in aqueous solution of 0.1 M H2SO4. The electrochemical polymerization of o-anisidine takes place in the presence of metanilic acid monomer and uniform, strongly adherent coating was obtained on the substrate. The electroactivity of copolymer was studied by cyclic voltammetry and AC impedance techniques. There is an increasing anodic current due to oxidation of metanilic acid monomer at the surface of the electrode when the applied potential is cycled from −0.2 V to 0.8 V. These deposits were characterized by Fourier transform infrared (FTIR) spectroscopy, UV–vis and TG/DTA techniques. The effect of various concentrations of PASM copolymer solution in acid rain corrosive media has been studied through potentiodynamic polarization, AC impedance and I–E curve methods. The soluble form of polymeric solution provided better anti-corrosive behavior in artificial acid rain solution.