Superior thermally conductive, mechanically strong and electrically insulating nacre-mimetic chitosan/boron nitride nanosheet composite via evaporation-induced self-assembly method

The development of electronic devices and the strict application environment put forward more requirements on the heat dissipation materials. However, it is still a challenge for thermal management materials to simultaneously possess high thermal conductivity , strong mechanical property and excellent electrical insulation. Herein, inspired by the special structure and function of natural nacre , we report on a large-scale and high-performance nacre-mimetic composite with boron nitride nanosheet (BNNS) as the “brick” and chitosan as the “mortar” via a green, simple evaporation-induced assembly technique. The nacre-mimetic composite film presents high TC of 26.3 W/(m·K) and superior electrically insulating due to well-aligned BNNS and strong interface interaction. In addition, even at BNNS contents as high as 70 wt%, the composite films still possess a tensile strength of 104.5 MPa and a Young's modulus of 8.7 GPa. The composite film used as a thermal interface material for cooling LED chip demonstrates higher heat dissipation efficiency than commercial silicone pad. This approach of constructing nacre-mimetic composite film with an oriented structure offers potential applications for heat dissipation in new portable electronic equipment.