Electrochemical synthesis of metal oxide doped poly(N-vinyl carbazole)s on steel and investigation of anticorrosive properties

In this study, in the presence of three different metal oxides (MnO2, TiO2, ZrO2), MnO2 doped poly(N-vinyl carbazole) (PNVnCz@MnO2), TiO2 doped poly(N-vinyl carbazole) (PNVnCz@TiO2) and ZrO2 doped poly(N-vinyl carbazole) (PNVnCz@ZrO2) films were synthesized by electropolymerization of N-vinyl carbazole monomer on the surface of 304 stainless steel by cyclic voltammetry method in tetrabutylammonium perchlorate containing anhydrous acetonitrile solution. Electrochemical synthesis of poly(N-vinyl carbazole) films was carried out in three different concentrations (0.05%, 0.10%, 0.15%) of each metal oxide. In order to determine the optimum amount of metal oxide, the recorded potentiodynamic polarization curves in 1 M H2SO4 solution of stainless steel electrodes covered with PNVnCz@MnO2, PNVnCz@TiO2, PNVnCz@ZrO2 films synthesized at different metal oxide concentrations were compared and it was determined that PNVnCz films synthesized at 0,10% metal oxide (MnO2, TiO2, ZrO2) concentration provided the best protection. The synthesized metal oxide doped PNVnCz coatings were characterized by ATR-FTIR and SEM. The corrosion performances of PNVnCz@MnO2, PNVnCz@TiO2 and PNVnCz@ZrO2 coatings were investigated by Eocp-time curves, potentiodynamic polarization (PP) and electrochemical impedance spectroscopy (EIS) methods. The results were compared with the data of undoped PNVnCz and it was observed that PNVnCz films doped with metal oxides provided better protection against corrosion of stainless steel in 1 M H2SO4 environment. When the corrosion performances of metal oxide doped PNVnCz films were compared, it was determined that protection efficiencies followed the order of PNVnCz@TiO2>PNVnCz@ZrO2>PNVnCz@MnO2 according to both of the PP and EIS results.