Effective protection of high-performance dopamine-based corrosion inhibitor on metal surface

To improve the service life of the Q235 steel in harsh environments, a high-performance inhibitor of modified dopamine was successfully synthesized between dopamine and polyethylene glycol diacrylate. The electrochemical behaviors of Q235 steel in 1 M HCl and 3.5% NaCl solutions with and without inhibitor were evaluated at 298 K. The result revealed that the addition of modified dopamine inhibitor could be effectively restrain the corrosion of Q235 steel. Simultaneously, when the modified dopamine inhibitor was 100 mg/L, the corrosion current density (icorr) of Q235 steel in 1 M HCl and 3.5% NaCl solutions decreased by 16 and 24 times, respectively. At this case, the corrosion inhibition efficiency (IE) increased from 59.1% to 69.2%–93.7% and 96.5% in 1 M HCl and 3.5% NaCl solutions when the inhibitor was changed from primordial dopamine (PD) to modified dopamine (MD), respectively. The improvement of these properties was due to the high coverage and strong adsorption of modified dopamine on steel surface.