Magnetic‐Targeted and Light‐Triggered Self‐Healing Microcapsules for Targeted Restoration of Damage‐Prone Insulating Material Zones

ABSTRACT Recent advances in microencapsulation technology have emerged as a promising approach for achieving self‐healing of electrical and mechanical damage in epoxy resin. Nevertheless, current implementations face dual challenges: (1) Dependency on external stimuli (elevated temperature, pH variations, or humidity) for microcapsule activation, precluding non‐contact self‐healing mechanisms; (2) Compromised matrix performance through reduced mechanical strength and dielectric integrity. To address these issues, this work innovatively presents a method to fabricate magnetic‐targeted natural photosensitive microcapsules. By incorporating Fe 3 O 4 @SiO 2 magnetic nanoparticles into the shells of photosensitive microcapsules via interfacial polymerization with a core‐shell structure, the microcapsules gain targeting migration ability and UV shielding function. The resulting magnetic‐targeted UV light‐sensitive microcapsules/epoxy composite insulating materials can achieve non‐contact damage repair using natural light. Moreover, the magnetic targeting enables directional migration of the microcapsules to the damage site in the matrix, significantly enhancing their utilization rate. Results show that, at a microcapsule doping concentration of 2 wt%, the tensile properties of the epoxy resin increased by 16.3% compared to pure epoxy resin, with minimal change in insulation strength and dielectric properties. Furthermore, the magnetically targeted natural photosensitive microcapsules can effectively repair surface cracks and electrical tree damage in epoxy resin, restoring the composite material's insulating property to 92.1% of its pre‐damage state after self‐healing.