SPECTROSCOPIC STUDY OF POLYTOLUIDINES IN THE UV-VISIBLE AND IR REGIONS

Electropolymerization of o-toluidine (o-methylaniline) and m-toluidine was carried out in acidic aqueous solution, and UV-visible and IR spectra of the resulting polymer films were obtained at various electric potentials and pHs. In Na2SO4 aqueous solution, poly(o-toluidine) gave considerably different UV-visible spectra from polyaniline, whereas, in HCl (pH approximately 0), the spectra of poly(o-toluidine) changed in the same way as polyaniline when the potential was varied. This spectral change depended also on counterion. This suggests that the intermediate state (radical cation) of poly(o-toluidine) is unstable in a neutral solution especially when a large counter ion exists, which is contrast to polyaniline. The dependency of the FT-IR spectra of poly(o-toluidine) on the potential and pH supported also the above result of UV-visible spectra. From both UV-visible and IR spectra under various conditions, it was found that o-toluidine and m-toluidine give the same polymer.