The soluble copolymers, poly (aniline-co-o-toluidine) and poly (pyrrole-co-o-toluidine) were synthesized by chemical oxidative copolymerization using ammonium persulphate as an oxidant in hydrochloride aqueous medium and characterized by FTIR spectroscopy. The polymers were dissolved in N-methyl-2-pyrrolidone and casted by solution evaporation on to the metallic substrate. The corrosion performance of the poly (aniline-co-o-toluidine) and poly (pyrrole-co-o-toluidine) coatings on carbon steel was studied by conducting immersion tests and electrochemical tests which include free corrosion potential measurements and potentiodynamic polarization measurements. The tests were conducted in 0.1 M HCl and 5% NaCl solution. The performance of coating in open atmosphere was also evaluated by conducting atmospheric exposure test. The surface morphology of the copolymer coatings were studied by scanning electron microscopy (SEM). The anticorrosive properties of copolymer coatings were also compared with polyaniline and poly (o-toluidine) coatings. In general the performance of poly (aniline-co-o toluidine) copolymer was found better than poly (pyrrole-co-o-toluidine) and homopolymer.
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