Lurid Bolete-Inspired Damage Reporting Coating with Simultaneous Weathering and Corrosion Resistance: Construction Strategy and Real-Time Degradation Monitoring

Abstract

Organic protective coatings encounter significant challenges in the face of mechanical damage, weathering degradation, and corrosion activities. Developing coatings that feature both autonomous damage reporting and enhanced durability is a promising yet challenging endeavor. In this study, inspired by the “damage coloration” of lurid bolete, a multifunctional smart coating integrating color/fluorescence damage reporting, weathering resistance, and active corrosion protection capabilities is developed by incorporating microcapsules encapsulated with crystal violet lactone (CVL) and cerium oxide (CeO₂) nanoparticles into polyurethane (PU) resins. CVL, a damage-reporting indicator exhibiting both color and fluorescence emission, is encapsulated within PU/poly-(urea formaldehyde) (PU/UF) microcapsules. CVL is released from the microcapsules upon damage, exhibiting localized fluorescence enhancement under UV irradiation and an intense blue coloration resulting from the chromogenic reaction with CeO₂ nanoparticles. In addition to initiating the chromogenic reaction of CVL, the CeO₂ nanoparticles confer outstanding weathering resistance and active corrosion protection to the coating matrix through their UV absorption and corrosion inhibition properties. The performance improvement of the composite coating in terms of weathering resistance and corrosion resistance is verified by in situ transmittance testing and real-time atmospheric corrosion monitoring.