Spectroelectrochemical study on the copolymerization of o-aminophenol and aminoterephthalic acid

The electrochemical copolymerization of aminoterephthalic acid (ATA) and o-aminophenol (OAP) was carried out on platinum electrodes in acidic medium. The obtained material, poly(ATA-co-OAP), can be deposited by cyclic scanning of the potential in a wide potential range and shows significant electroactivity. However, it was observed that a copolymer with less overoxidation defects is obtained at inversion potentials where only OAP monomer (and not ATA monomer) is oxidized. The successful incorporation of unoxidized ATA monomers to the growing copolymer chain was confirmed by in situ FTIR spectroscopy and XPS, which suggested a monomer ratio close to 1:2 (ATA:POAP) within the obtained copolymer material. The redox switching of poly(ATA-co-OAP) in acidic medium involves reversible benzenoid-quinoid and phenoxazine-phenoxazone conversions but carboxylic groups do not participate actively on these transformations.