Reinforcement of microwave absorption and thermal conductivity of polydimethylsiloxane achieved by metal-organic framework-derived carbon nanotube/boron nitride flake heterogeneous structure

Due to the rapid advancement of electronic devices towards miniaturization, high-integration, multi-functionality, high-power, and high-frequency, it is necessary to design thermal interface materials (TIMs) that possess exceptional thermal conductivity as well as good capabilities for absorbing electromagnetic waves. In this report, carbon nanotubes (CNTs) containing cobalt (Co) nanoparticles have been in-situ grown on the surfaces of boron nitride flakes (BNFs) using the Co nanoparticles as catalysts which formed by the high-temperature pyrolysis and reduction of zeolite-imidazolate skeleton. Then, a multifunctional heterogeneous structure of Co@CNT/BNFs has been developed with tunable microwave absorption (MA) property and high thermal conductivity, which can be applied to enhance the MA performance and thermal conductivity of polymers simultaneously. The minimum reflection loss can reach -46.6 dB and a broad absorption bandwidth of 5.92 GHz can be obtained when adjusting the content of Co@CNT/BNFs in the absorbers. Furthermore, the thermal conductivity of the polydimethylsiloxane measured using the transient hot-wire apparatus is 0.72 W/(m & sdot;K) when the content of Co@CNT/BNFs is 30 wt%, exhibiting excellent heat dissipation performance in thermal management. This work is significant for investigating MA packaging and high thermally conductive TIMs for the electronic devices.