Electrochemical copolymerization study of o-toluidine and o-aminophenol by the simultaneous EQCM and in situ FTIR spectroelectrochemisty

The electrochemical synthesis and characterization of a copolymer, poly(o-toluidine-co-o-aminophenol), were conducted using in situ piezoelectric FTIR spectroelectrochemisty. The monomer feed ratio strongly affects the copolymerization rate and the properties of the copolymer during the electrosynthesis in 0.5 M H2SO4 aqueous solution. The effects of scan rate and pH value on the electrochemical activity of the obtained copolymer were also studied. The copolymer synthesized in higher molar ratio of o-toluidine/o-aminophenol exhibited good electrical activity and stability in a broad pH range. The copolymerization mechanisms of o-toluidine and o-aminophenol were deduced. The copolymer formed through the head-to-tail coupling of the two monomers via –NH– groups was a new polymer rather than a mixture of poly(o-toluidine) and poly(o-aminophenol).