Highly conductive flexible thermal interface material based on vertically oriented continuous carbon fiber arrays anchored in silicone rubber

Abstract As the power density of integrated circuits in electronic devices continues to rise, thermal management has emerged as a critical technical barrier limiting performance enhancement. To address this challenge, an innovative‐oriented filler strategy has been proposed based on an in‐depth analysis of the spatial distribution effects of composite fillers. This strategy combined the properties of one‐dimensional continuous carbon fibers (C‐CF) with two‐dimensional boron nitride (BN) to successfully design and fabricate a flexible thermal interface material based on vertically oriented liquid silicone rubber/boron nitride/continuous carbon fiber (LSR/BN/C‐CF). During the material preparation process, the C‐CF was precisely manipulated and wound layer by layer into the mold to form a vertically oriented array structure. Subsequently, the array was infiltrated and anchored with LSR or LSR/BN, ensuring structural robustness while significantly enhancing thermal conductivity (TC). The through‐plane TC was effectively increased by the multiple direct heat conduction pathways that C‐CF created in the thickness direction in this composite. According to experimental data, at 10 wt% BN loading, the composite's TC reached 3.315 W/mK, a 28‐fold increase over pure LSR. This innovation provided a viable solution to the thermal management challenges faced by electronic devices. It explored new directions for developing composites with excellent vertically highly oriented properties for electronic device thermal management applications. Highlights Continuous carbon fibers are vertically aligned in the silicone rubber. Boron nitride connects carbon fibers, enhancing heat transfer. It enables easier continuous production, greatly reducing complexity and costs. A continuous heat conduction path is formed in the vertical direction. Multi‐dimensional filler synergy improves performance.