Enhancing thermal conductivity of silicone rubber composites by in-situ constructing SiC networks: A finite-element study based on first principles calculation
Dongliang Ding, Shiyu Zhang, Haoyu Liang, Xu Wang, Ya Wu, Yuanming Ye, Zhen‐Guo Liu, Qiuyu Zhang, Guangzhao Qin, Yanhui Chen
Abstract
Polymer composites as thermal interface materials have been widely used in modern electronic equipment. In this work, we report a novel method to prepare highly through-plane thermally conductive silicone rubber (SR) composites with vertically aligned silicon carbide fibers (VA-SiCFs) entangled by SiC nanowires (SiCNWs) networks. First, a series of carbon fibers (CFs) skeletons were fabricated in sequence of coating poor thermally conductive polyacrylonitrile-based CFs with polydopamine, ice-templated assembly, and freeze-drying processes. Furthermore, VA-SiCFs networks, i.e., long-range continuous SiCFs-SiCNWs networks, based on the prepared CFs skeletons, were in-situ obtained via template-assisted chemical vapor deposition method. The thermal conductivity enhancement mechanism of VA-SiCFs networks on its SR composites was also intensively studied by finite element simulation, based on the first principles investigation of SiC, and Foygel’s theory. The in-situ grown VA-SiCFs networks possess high intrinsic thermal conductivity without the thermal interface between fillers, acting as the high-efficiency through-plane long-range continuous thermal conduction path, in which the SiCNWs were the in-plane “thermal spreader”. The VA-SiCFs/SR composites reached a high through-plane thermal conductivity, 2.13 W/(m·K), at the filler loading of 15 vol.%, which is 868.2%, and 249.2% higher than that of pure SR sample, and random-CFs@polydopamine (PDA)/SR composites at the same content, respectively. The VA-SiCFs/SR composites also exhibited good electrical insulation performance and excellent dimensional stability, which guaranteed the stable interfacial heat transfer of high-power density electronic devices.