Manipulation of polymer layer characteristics by electrochemical polymerization from mixtures of aniline and ortho‐phenylenediamine monomers

The influence of adding ortho‐phenylenediamine (OPDA) during the polymerization of aniline on the characteristics of the resulting polymer film was examined. When using a platinum electrode, the deposits were obtained from solutions containing 0.1 mol dm^?3 aniline and 1, 5, or 10 mmol dm^?3 OPDA. The deposits were also prepared from solutions containing 0.5 mol dm^?3 aniline and 5, 10, or 50 mmol dm^?3 OPDA. In both cases, 3 mol dm^?3 phosphoric acid solution was used as a supporting electrolyte. The characteristics of the obtained layers were investigated through the catalytic effect of different polymer layers on hydroquinone/quinone (H₂Q/Q) test redox system. The results obtained confirm the earlier established catalytic effect on the potential of the redox reaction by shifting it to more reversible values. However, as the concentration of OPDA was increased, the resulting limiting current decreased, thus indicating in the presence of OPDA a lower population of the available active centers necessary for the catalytic reaction to proceed. The influence of OPDA on polymer characteristics was also studied by using scanning electron microscopy as well as electrochemical impedance spectroscopy. The polymer was synthesized on a stainless steel electrode (13% Cr) from a solution containing 0.5 mol dm^?3 aniline and 5, 10, or 50 mmol dm^?3 OPDA. The layers were tested in chloride‐containing solutions by monitoring the open circuit potential. The results obtained suggest that, by increasing the concentration of OPDA, the time of OCP in the passive region of stainless steel is prolonged. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009