Electrochemical Polymerization of Aniline and N-Alkylanilines

N-Alkylanilines were electrochemically oxidized in H₂SO₄ aqueous solution. The electrochemical, spectroscopic, and electric properties of the oxidation products were investigated by comparing them with those of polyaniline. Although the film-forming ability on the electrode surface decreases with the bulkiness of the alkyl group, the solubility of the oxidation products increased with increasing the bulkiness of the alkyl group. The oxidation products of N-ethyl-, N-propyl-, and N-butylaniline are almost soluble in THF. From the GPC elution pattern showing the existence of high molecular weight components, formation of poly(N-alkylaniline)s was confirmed. The electric conductivities of these polymers were decreased by the bulkiness of the substituents. An increase in the conductivity accompanies the shift of the absorption bands in the near-IR region to the longer wavelength and the significant changes of ESR signals.