Preparation and Repeatable Self‐Healing Performance of Microcapsules With a Dual‐Repair Mechanism

To address the limited repeatability of conventional microcapsule‐based healing systems, repeatedly self‐healing microcapsules (RSMCs) were developed by encapsulating a dual‐component healing agent rich in multiple dynamic bonds. This approach integrated extrinsic with intrinsic self‐healing mechanisms: extrinsic repair was achieved via the thiol‐ene click reaction upon capsule rupture, while intrinsic repair occurred through dynamic bond exchange. RSMCs were incorporated into a structurally similar polythiourethane (PTU) elastomer with intrinsic self‐healing capabilities to fabricate a self‐healing coating (RSMCs/PTU). The structural similarity between the microcapsules and the PTU matrix ensured excellent interfacial compatibility, resulting in an elongation at break and tensile strength of up to 5.03 MPa and 269.44%, respectively. Furthermore, benefiting from its dual‐mode repair mechanism, the coating achieved two‐cycle repair at the same damaged site. The 1st healing process was achieved via UV irradiation at room temperature for 20 min, while the 2nd healing was performed under thermal treatment at 60°C for 10 h. This work offered a new solution to the limitation of repair cycles in microcapsule‐type self‐healing materials, thereby extending the service life of polymer materials.