Epoxy composite with significantly improved thermal conductivity by constructing a vertically aligned three-dimensional network of silicon carbide nanowires/boron nitride nanosheets

The trend of miniaturization, integration and multi-function of modern electronics leads to the speedily increased power density which makes heat dissipation a crucial issue. Herein, epoxy based composites with highly enhanced through-plane thermal conductivity were successfully prepared by constructing a free-standing and vertically aligned silicon carbide nanowires (SiCw)/functionalized boron nitride nanosheets (f-BNNS) framework through modified filtration strategy. The synergetic effect between hybrid fillers ensured highly efficient channels for phonons in vertical direction that the maximum thermal conductivity reached 4.22 W/mK at a low hybrid filler loading of 21.9 vol%, increased by 1658% in comparison to that of pure epoxy. Due to the entanglement effect of SiCw/f-BNNS framework and the enhanced interface interaction by BNNS modification, the interfacial thermal resistance between filler/filler and filler/matrix were both reduced a lot compared with random dispersion method. Exceptional heat dissipation capability of the vertically orientated architecture was also demonstrated by theoretical simulation and chip encapsulation applications. In addition, the coefficient of thermal expansion of composite reached as low as 41.1 ppm/degrees C, only half of the epoxy resin (83.5 ppm/degrees C). This work provides a novel strategy for fabricating polymer based composites with superior through-plane thermal conductivity in thermal management applications.