Highly thermally conductive polymer composite enhanced by two-level adjustable boron nitride network with leaf venation structure

Thermally conductive polymer-based composites are extensively used in many fields as thermal control materials. Their thermal conductivity can be effectively improved via the construction of a 3D thermal conduction network. However, multiple 3D networks have low density and lack elasticity and flexibility, leading to suboptimal thermal conductivity. In this study, a composite with high thermal conductivity is obtained by building a two-level adjustable boron nitride (BN) network with leaf venation structure in an epoxy resin matrix, and the density and orientation of the network are controlled by compression. The primary and secondary BN networks construct efficient phonon conduction channels. Moreover, the polydopamine interface between the thermally conductive network and substrate greatly reduces interfacial phonon scattering. The in-plane and cross-plane thermal conductivities of the composite at 35.9 wt% BN loading reach 10.20 and 4.95 W m−1K−1, respectively. And the composite has excellent electrical insulation, all making it promising for the thermal management of electronic equipment and thermal interface material in application prospects, such as the soft robotics, flexible smart devices, and aerospace.