Self‐Diagnostic and Self‐Healing Intelligent Coatings Based on Microcapsules by Microfluidic Technology

ABSTRACT Monitoring and repair of microcracks at early stages are critical because their formation and propagation typically degrade the protective performance and service life of coatings. Currently, microcapsules are widely employed as carriers for functional agents such as diagnostic and healing agents. However, there remains a high demand for microcapsules with a small, uniform size and controllability used for monitoring and self‐healing of coating microcracks. Herein, core‐shell microcapsules of ~0.95 μm with good uniformity were prepared by the integration of microfluidic technology and interfacial polymerization, featuring a polyurea shell encapsulating a core material composed of rhodamine B (Rh B) as the diagnostic agent, 1,3‐bis(epoxypropoxy)tetramethyldisiloxane (B3001) as the healing agent, and triarylsulfonium hexafluorophosphate in propylene carbonate (PI 6992) as the photoinitiator. An intelligent coating with dual self‐diagnosis and self‐healing functions was subsequently developed through the encapsulation of these agents. Monitoring of the microcrack was achieved by observing the fluorescent reaction, and the self‐healing was realized through UV‐triggered cross‐linking polymerization of the healing agent. Both the fabrication method for microcapsules and the dual‐functional coating have important economic benefits and practical application prospects in special environments.