Controlling the morphology and properties of electrodeposited polyaniline layer on TiO2 nanotubes

Abstract

Polyaniline (PANI) layers were electrodeposited, as the conductive emeraldine salt phase (PANI (ES)), on the surface of titanium dioxide nanotubes (TiO2 NTs) to evaluate the protective and photo(electro)chemical performance. TiO2 NTs plates were obtained by anodization, in a two-electrode in the undivided cell. The adjustment of the electropolymerization parameters (e.g. aniline concentration, cycles number in cyclic voltammetry, TiO2 cathodic polarization) allowed the control of the PANI (ES) morphology and film thickness, changing the charge recombination dynamics on the PANI (ES)/TiO2 and PANI (ES)/liquid interfaces. It was observed that lower aniline concentrations resulted in the best control of the electropolymerization process, which ensured the deposition of thin films. The TiO2 NTs/PANI (ES) interface was characterized by absorption and vibrational spectroscopies, and scanning electron microscopy. Electronic and photo(electro)chemical properties of the TiO2 NTs/PANI (ES) films were characterized by photoelectrochemical measurements and electrochemical impedance spectroscopy.