Thermal conductivity and compressive strength of silicone rubber composites enhanced by aligned carbon nanofiber scaffold

Abstract Polymer composites with high enough thermal conductivity, known as thermal interface materials (TIMs), are continuously pursued in the thermal management of high‐power density electronic and energy devices. In this article, to improve the heat transfer performance of TIMs, we constructed an aligned carbon nanofiber (CNFs) scaffold via the freeze‐casting method to serve as heat conduction paths in the TIMs. The composites of aligned CNF scaffold and silicone rubber were obtained by immersing the aligned scaffold into the silicone rubber with vacuum assist. We studied the influences of different CNFs diameters on the thermal conductivity of the composites, the pore sizes of the aligned CNF scaffold and the thermal conductivity of the composites fabricated under different freezing temperatures, and also the mechanical properties of the composites. Owing to the aligned scaffold, providing directional and continuous heat conduction paths, the thermal conductivity of the composites reached 3.17 W/(m·K) at 7.73 vol% CNFs. Additionally, the compressive strength and fracture strain of the composites were also greatly improved.