Electrochemical synthesis, characterization and electrochromic behavior of poly(4-aminodiphenylamine-co-4,4′-diaminodiphenyl sulfone)

A new electroactive and electrochromic copolymer of 4-aminodiphenylamine (ADPA) and 4,4'-diaminodiphenyl sulfone (DADPS) was synthesized electrochemically in 0.5 M H2SO4 in water and ethanol medium. The electrochemical synthesis of the copolymer by deposition on a glassy carbon electrode (GCE) and its characterization were carried out using cyclic voltammetry (CV). The voltammograms exhibited different patterns of behavior with different feed concentrations of DADPS. Equimolar concentrations of ADPA and DADPS or the combination with slight excess concentration of DADPS demonstrated very efficient growth of the copolymer film on the surface of the GCE. The copolymer is highly soluble in dimethyl sulfoxide (DMSO). The scan rate of this copolymer on GCE showed linear variation, revealing the film's excellent electroactive adherent properties. The effect of pH on the copolymer film showed that the polymer was electrochemically active up to pH 7.0. Spectroelectrochemical analysis of the copolymer film, carried out on an indium tin oxide (ITO) plate, showed multi-color electrochromic behavior when the applied potential was changed. The copolymer was characterized by FTIR and H-1 NMR spectral data. The surface morphology was studied using SEM analysis and the grain size of the copolymer was measured using XRD studies and found to be 28 nm. The electrical conductivity of the copolymer was 3.48 x 10(-2) S cm(-1), as determined using a four-probe conductivity meter. (C) 2012 Elsevier Ltd. All rights reserved.