Electrochemical synthesis of polypyrrole/polyhedral oligomeric silsesquioxane nanocomposite on copper for corrosion protection

Electrochemical synthesis of polypyrrole (PPy)/polyhedral oligomeric silsesquioxane (POSS) nanocomposite on copper is studied using cyclic voltammetry technique in aqueous sodium benzoate solution. The resulting PPy/Cu and PPy/POSS/Cu films were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis. The performance of PPy and PPy/POSS nanocomposite as protective coatings against corrosion of Cu in 3.5% NaCl solution is assessed by potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The corrosion potential for PPy/POSS/Cu is positively shifts by 0.071 V in comparison with uncoated copper. The corrosion current density is found to be 24.08, 7.23, and 2.101 μA/cm2 for uncoated Cu, PPy coated Cu and PPy/POSS coated Cu, respectively. The results showed that by adding the POSS nanostructures within PPy matrix, the current density of the monomer oxidation decreased, significantly. The EIS studies indicated that the charge transfer resistance increases with the presence of PPy/POSS and accordingly, protection of copper improved against corrosion action.