Collect. Czech. Chem. Commun. 1989, 54, 3154-3161

Electropolymerization of aniline and some of its derivatives

Ludmila Dempírová and Zdena Adamcová

Department of Physical Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6


The effect of substitution on the aromatic ring of aniline and in its amino group on the potential of polymerization in aqueous medium and on the charge passed during polymerization was studied. The formation of polymer films on the working electrode and their electrochromic changes were also examined. From the electro-oxidation of aniline, the number of reversible and irreversible steps, the number of electrons exchanged and the type of oxidation mechanism were found. Thickness of a single layer of polyaniline, formed by cycling the potential in the range –0.2 V, +1.4 V(vs SCE) at a polarization rate of 5 mV/s, was estimated considering the oxidation mechanism of aniline. The electrochemical behaviour of aniline in anhydrous acetonitrile medium was also studied. It was found by blocking the m- and p-positions in aniline by a methyl substituent that polymerization of aniline occurs through the p-position. The porosity of the polymer films was estimated from the diffusion coefficient values for 1.10-3M K3[Fe(CN)]6 in 0.1M-KCl calculated from the Randles-Sevcik equation for measurements on Pt electrodes with a polymer film, compared with the tabulated values for a bare Pt electrode.