Electrochemical and spectroelectrochemical evidences for copolymer formation between 2-aminodiphenylamine and aniline

Electrochemical copolymerization of 2-aminodiphenylamine (2ADPA) with aniline (ANI) was carried out in aqueous hydrochloric acid by using cyclic voltammetry. In addition, cyclic voltammetry was used to evaluate the differences in electrochemical characteristics of the copolymer in comparison with the corresponding homopolymers, polyaniline (PANI) and poly(2-aminodiphenylamine) (P2ADPA). A growth equation of the copolymer films in terms of concentration of 2ADPA and cycle numbers, C-n, was deduced as Q(G) = 7.11 x 10(-7) [2ADPA](-1.1) C-n(2.8) by utilizing the charge associated for film deposition. The variation of peak currents and peak potentials with respect to sweep rates were compared between copolymer and PANI films. Further support for copolymer formation was obtained through spectroelectrochemical studies. This was done by recording UV-visible spectra during constant potential electropolymerization of a mixture of monomers, ANI and 2ADPA, on an indium-tin oxide-coated glass electrode. The appearance of a band at 520 nm in contrast to the spectra of PANI reveals that the copolymer is structurally different from PANI. (C) 2001 The Electrochemical Society.