THE MECHANISM OF ELECTRODEPOSITION AND MOLECULAR-STRUCTURE OF POLY(P-AMINOAZOBENZENE)

The mechanism of electrochemical deposition of poly(p-aminoazobenzene) (PAAB) on a Au electrode from acetonitrile solutions containing pyrid ine was studied by cyclic voltammetry and potential-step experiments. Cyclic voltammograms indicate that the polymer deposits on the substra te only if the solubility of the oligomeric products of PAAB oxidation drops as a result of growing chain. As it follows from the potential- step experiments, the process of electrodeposition is instantaneous an d three dimensional (3DI). At higher pyridine content this mechanism c hanges into progressive two-dimensional nucleation and growth (2DP). E x situ FT-IR and in situ Raman spectra were recorded. The spectroscopi c data allowed us to establish the molecular structure of polymers dep osited at 1.0 and 1.2 V. It appeared that in both cases the deposits a re mixtures of at least two structures, the first one of linear struct ure formed through head-to-tail (C-N) or head-to-head (N-N) coupling a nd the second one built by ortho-substitution.