Preparation and Corrosion Resistance of Microcapsule-based Self-reporting and Self-healing Epoxy Coating

• • Optimal microcapsule synthesis parameters—400 r/min stirring, 3 h reaction, 0.5% EMA—yield DCF and TO loadings of 1.3% and 35.82%, respectively; these values directly determine reporting sensitivity and healing capacity, with TO loading above 35% ensuring sufficient healing agent for crack filling. • • DP9wt.% coating achieves an impedance modulus of 2.88×10^5 Ω·cm^2 after 240 h seawater immersion, one order of magnitude higher than the EP coating, indicating that 9 wt.% microcapsules provide the best balance between barrier enhancement and microcapsule-induced defects. • • Wet adhesion loss for DP9wt.% is only 37.7%, the lowest among all formulations, demonstrating that the healing reaction of TO at the interface mitigates coating delamination, a critical failure mode in marine immersion service. • • DCF released from ruptured microcapsules reacts with residual amine groups to form a red precipitate under natural light and yellow fluorescence under UV, enabling dual-mode visual detection of damage; this self-reporting function operates without external power or instrumentation, offering a practical inspection tool for field applications.