Investigation of pH Effect on the Anticorrosion Behavior of Smart Nanocoating Based on the Epoxy Ester/Nanopolyaniline Particles

Anticorrosive coating has been prepared through incorporation of synthesized nanopolyaniline into the epoxy ester resin. Anticorrosive performance of the manufactured coating was evaluated in the environments with different pH values based on the HCl and NaOH for acidic and basic environments, respectively. The anticorrosion measurements were performed by the electrochemical impedance spectroscopy (EIS) technique during 95 days of immersion time. Corrosion mechanism of coating was determined by the Nyquist plots analysis in different environments. The influence of pH variations on the anticorrosion performance of coating was quantitively investigated by the electrochemical modeling. The obtained results showed smart corrosion inhibition mechanism of nanopolyaniline particles and high anticorrosive ability of the coating. Where, the reaction between released anionic inhibitor and metallic cations causes to formation of a second barrier layer in the defected situations and enhancement of coating resistance against the corrosive ions. In addition, the coating showed better performance in the environments with less corrosive ions concentration.