INVESTIGATION OF THE EARLY STAGES OF THE ELECTROPOLYMERIZATION OF O-TOLUIDINE BY UV-VIS REFLECTANCE SPECTROSCOPY

The electrochemical synthesis of poly(ortho-toluidine) in acid medium was studied by 'in situ' UV-Vis differential reflectance spectroscopy. Thus, it was possible to follow the early stages of the formation of the conducting polymer at a gold electrode. With low concentrations of o-toluidine, an intermediate species was formed on the electrode surface during the first cycles. UV-Vis reflectance spectra of this species, recorded 'in situ', showed that it is different from that of the polymer itself, which can be observed after several potential cycles with low concentrations of monomer, or at the first cycle with concentrations of o-toluidine greater than 0.1 M. The likely role of this intermediate species as a precursor of the electropolymerization process is discussed.