Self-healing nanocomposite coatings containing organic-inorganic inhibitors functionalized dendritic silica nanocontainers for synergistic corrosion protection of carbon steel

Corrosion inhibitors are crucial for self-healing of the coatings. However, the corrosion inhibition effect of single inhibitor is still limited. In this work, the self-healing nanocomposite coatings (HZK/EP) were prepared based on the synergistic effect of L-histidine (L-His) and Zn2+ ions. Dendritic silica (KCC-1) is used as nanocontainers to realize effective loading and release of inhibitors, thereby greatly improving anticorrosion ability of EP compared with the direct addition of inhibitors. Electrochemical impedance spectroscopy (EIS) results show that HZK/EP has a high |Z|0.01 Hz value of 3.32 × 1010 Ω·cm2 after 40 days of immersion in 3.5 wt% NaCl solution. His-Zn/KCC-1 endows epoxy coating with the excellent self-healing performance, which can be attributed to the fact that the lone pair electrons of N or O atoms of L-His can coordinate with the empty orbital of Zn2+ ions to form a complex.