Application of electrochemically produced and oxidized poly(3,4-ethylenedioxythiophene) as anticorrosive additive for paints:: Influence of the doping level

This work investigates the resistance against marine corrosion of an epoxy-based coating modified by the addition of electrochemically produced and oxidized poly(3,4-ethylenedioxythiophene) (PEDOT). For this purpose, electrodeposition of PEDOT was performed on steel electrodes by electrochemical polymerization of 3,4-ethylenedioxythiophene. The doping level of the resulting material was increased by chronoamperometry and chronopotentiometry (CP), three different oxidation degrees being achieved. The electrochemical and electrical properties of such three samples, which were used as anticorrosive additives, were examined. Furthermore, the physical properties of the coating before and after addition of the conducting polymers were characterized using FTIR, thermal analyses, and mechanical properties evaluations. Accelerated corrosion tests indicated that the polymer with the highest amount of positive charge per monomeric unit, which was achieved by CP, enhances considerably the anticorrosive protection imparted by the coating. (c) 2006 Wiley Periodicals, Inc.