Self-healing and self-reporting behavior of epoxy coating with BTA+APhen@MSN on carbon steel

Purpose The purpose of this paper is to prepare smart coatings with self-healing and self-reporting dual functionalities. Design/methodology/approach Benzotriazole (BTA) and 1,10-phenanthroline-5-amine (APhen) were encapsulated within mesoporous silica nanocontainers (MSN) via one-step method. Then, BTA+APhen@MSN were mixed with epoxy for preparing BTA+APhen@MSN/EP coatings. The microstructure, structure and sustained-release properties of BTA+APhen@MSN nanocontainers were investigated by transmission electron microscopy, Fourier-transform infrared spectroscopy, Brunauer–Emmett–Teller analysis and UV-Vis spectroscopy. The warning performance and corrosion resistance of BTA+APhen@MSN/EP coatings were characterized by optical microscopy and electrochemical impedance spectroscopy. Findings BTA+APhen@MSN exhibit higher corrosion inhibitors loading capacity (31.2 wt.%) and higher corrosion inhibition efficiency (53.07%) than BTA@MSN and APhen@MSN. The BTA+APhen@MSN/EP coatings show excellent self-healing performance. After soaking in 3.5 wt.% NaCl solution for five days, the fitted resistance of scratched coatings increased by 18%. The BTA+APhen@MSN/EP coatings also show superior self-reporting capability, which can provide a warning of coating damage within 30 min by a visible color change. Originality/value The corrosion inhibitors and corrosion warning agent are encapsulated in a nanocontainer to prepare multifunctional nanocomposite. This multifunctional nanocomposite presents a new approach for designing smart coatings with self-healing and self-reporting dual functionalities.