Preparation and application prospects of polymer-based thermally conductive self-healing composites

Miniaturization and high integration of 5G electronics, aerospace components, and intelligent devices have caused severe heat accumulation, shortening the service life and degrading the reliability of devices. Traditional thermally conductive materials are inflexible, whereas most neat polymers are poor thermal conductors. Cyclic stress-induced structural cracks disrupt thermal pathways and increase interfacial thermal resistance. Combining high thermal conductivity, flexibility, and self-healing capability, polymer-based thermally conductive self-healing composites have emerged as promising thermal-interface materials. This review systematically summarizes extrinsic self-healing systems (microcapsules and microvascular networks) and intrinsic self-healing materials that mend through dynamic covalent bonds, supramolecular non-covalent interactions, and dual-dynamic crosslinking networks. The self-healing mechanisms, preparation strategies, and thermal management performance of self-healing materials are thoroughly discussed. Key bottlenecks, including the trade-off between high filler loading and self-healing efficiency, harsh repair conditions, unstable recovery of thermal conductivity, and insufficient validation in practical applications, are also analyzed. The review concludes with proposals for future research, covering multi-scale interface regulation, theoretical simulations of phonon transport, large-scale fabrication, and the development of multifunctional composites for electronic thermal management.