Active anti-corrosion and fluorescence self-detection coatings with mussel-inspired hexagonal boron nitride-based multifunctional nanocontainers

Considering the massive damage and substantial economic losses caused by metal corrosion, it is extremely urgent for researchers to develop more high-performance anti-corrosion coatings. Herein, an intelligent anti-corrosion epoxy coating system integrating active protection and fluorescence self-monitoring capabilities has been developed. This system utilizes mussel-inspired boron nitride nanosheets (BNNS) as multifunctional nanocontainers loaded with rhodamine hydrazide (R1) fluorescent probes. The mesoporous polydopamine (mPDA) modification improves the dispersibility of BNNS, and the prepared nanocontainer on this basis combines the excellent barrier performance of BNNS itself and the corrosion inhibition effect of mPDA and R1, enhancing the long-term anti-corrosion performance of the coatings. EIS test demonstrated that after 60 days of immersion in a 3.5 wt% NaCl solution, the BNNS-mPDA@R1 coating exhibited an impedance modulus of 7.75 × 10 10  Ω·cm 2 . Furthermore, the R1 probe generates a fluorescence signal by capturing the iron ions generated during early corrosion, enabling in situ self-detection of corrosion. The chelation-enhanced fluorescence(CHEF) mechanism of R1 for iron ions was verified through solid/liquid fluorescence spectra and quantum efficiency tests, demonstrating that R1 exhibits outstanding fluorescence-based self-monitoring capabilities, enabling in situ visualization and early-stage warning of coating degradation. In summary, this study provides novel insights into the design of multifunctional epoxy coatings that simultaneously achieve corrosion protection and self-warning, effectively promoting the development of the multifunctional coatings.