Fluorescein-loaded nanoflowers driven smart anticorrosion coating for hierarchically visually monitoring of early failure process

Monitoring early damages in protective coating and metallic structure before critical failures is essential to avoid potential safety crisis. Although self-reporting coatings have been demonstrated, achieving hierarchically visually monitoring for both coating damage and local corrosion, and meanwhile quantitatively evaluating corrosion warning intensity still remain challenging. In this study, novel anticorrosion coating system is prepared by comprising crosslinked polyurethane network and fluorescein-loaded nanosensors . At single coating damage sites, the constructed sensors release 2′,7′-dichlorofluorescein (DCF) probes to produce green fluorescence based on aggregation induced quenching phenomenon of DCF molecules. As the damage progresses into Mg alloy substrate, the DCF probes open loops to emit distinct red color at early corrosion sites. Furthermore, the early corrosion is quantitatively evaluated by converting reporting images to detailed gray values using a self-developed version extraction program ( VE ). This work lays the foundation to in-depth analyze early corrosion process through visually monitoring mechanisms, which opens new possibilities for the development of self-monitoring anticorrosion coatings. • ·A smart coating is composed of DCF-loaded HA flowers and polyurethane resin. • ·The coating can hierarchically report coating damage and interfacial corrosion. • ·Corrosion warning was quantitatively evaluated by vision extraction software.