Achieving significant thermal conductivity improvement via constructing vertically arranged and covalently bonded silicon carbide nanowires/natural rubber composites

Abstract

With the development of electronic devices, it is becoming increasingly important for thermal interface materials (TIMs) to efficiently and quickly remove the heat generated. However, due to the high thermal resistance of the interface between fillers as well as filler and matrix, this seriously affects the transfer of phonons at the interface. Herein, silicon carbide nanowires (SiCnw) were bonded to rubber with a strong interaction force by grafting small molecular functional groups on the surface of SiCnw, which could serve as a phonon expressway. Secondly, a three-dimensional (3D) functional SiCnw/natural rubber (3D f-SiCnw/NR) TIM with a highly oriented and interconnected thermal conductive network was successfully prepared through the freeze-casting method. The thermal conductivity of the composites could reach 0.856 W m⁻¹ K⁻¹ when the filler content was 8.89 vol%. Meanwhile, the excellent heat transfer ability, wonderful electrical insulation performance and good mechanical properties provided better reliability for the application of f-SiCnw/NR composites in thermal management. It is more valuable that this strategy provides a powerful way to prepare high performance rubber-based thermal-management materials.