Electropolymerization and characterization of COOH-functionalized poly(3,4-ethylenedioxythiophene): Ionic exchanges

The electropolymerization of COOH-functionalized 3,4-ethylenedioxythipohene was investigated by cyclic voltammetry, by anodic potential steps or by flow of a constant anodic current. Compared with PEDOT, an anodic shift of the oxidation polymerization potential is observed. Nevertheless the polymer film oxidation/reduction is shifted to more cathodic potentials, giving higher stored specific charges than those obtained from PEDOT films generated in similar conditions. The generated polymer shows a stable redox process, E0 = -0.04 V. EQCM results point to a p-doping process exchanging anions with solution, whereas a second reduction process at -0.77 V is related to a p-doping process exchanging cations. The new material is electrochromic: it is colourless in its oxidized state and blue colour in its reduced state. UV-Vis spectroelectrochemical results are similar to those obtained from PEDOT films. © 2011 Elsevier Ltd. All Rights Reserved.