Self-healable dual dynamic polyborosiloxane/BN composites with highly oriented thermal conduction networks for advanced thermal interface materials

The rapid escalation of power density in modern electronic devices has heightened the demand for efficient thermal interface materials (TIMs) to ensure system reliability and stability. Silicone composites incorporating hexagonal boron nitride ( h -BN) fillers are widely used. However, their performance is hampered by weak interfacial interactions between BN and the polydimethylsiloxane (PDMS) matrix, which induce structural defects, intensify phonon scattering, and compromise mechanical flexibility and environmental adaptability. Here, we report a facile and scalable synthesis of a dual dynamic crosslinked polyborosiloxane (DN-PBS) elastomer. With its intrinsic self-healing capability, DN-PBS was employed as the thermal interface material matrix, within which a three-dimensional hydroxylated h -BN (BNOH) thermally conductive network was assembled using a novel blade-coating/lamination/hot-pressing strategy. The resulting DNPBS/BNOH composites exhibited room-temperature self-healing and high thermal conductivity, thus addressing the challenge of ordered h -BN assembly. Moreover, the synergistic interactions between coordination and hydrogen bonds endowed the material with autonomous healing at room temperature and markedly suppressed interfacial phonon scattering. At a BNOH loading of 40 wt%, the composite exhibits a superior thermal conductivity of 8.9 W m −1 K −1 (representing a 39-fold enhancement) and an ultralow thermal resistance of 1.19K cm 2 W −1 . Simultaneously, it demonstrates exceptional mechanical compliance, characterized by a low Young’s modulus of 0.88 MPa and a high elongation at break of 433.8%, alongside intrinsic room-temperature self-healability. Moreover, the low dielectric constant and dielectric loss ensured minimal signal attenuation and energy dissipation, rendering the material highly suitable for thermal management in advanced electronic devices under complex service environments. This work provides a promising platform for next-generation high-performance TIMs in emerging electronics.