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.