Yan Qingwei, Dai Wen, Gao Jingyao, Tan Xue, Lv Le, Ying Junfeng, Lu Xiaoxin, Lu Jibao, Yao Yagang, Wei Qiuping, Sun Rong, Yu Jinhong, Jiang Nan, Chen Ding, Wong Ching-Ping, Xiang Rong, Maruyama Shigeo, Lin Cheng-Te
College of Materials Science and Engineering, Hunan University, Changsha, 410082, P. R. China.
Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences, Ningbo, 315201, P. R. China.
ACS Nano. 2021 Apr 27;15(4):6489-6498. doi: 10.1021/acsnano.0c09229. Epub 2021 Mar 18.
The rapid development of integrated circuits and electronic devices creates a strong demand for highly thermally conductive yet electrically insulating composites to efficiently solve "hot spot" problems during device operation. On the basis of these considerations, hexagonal boron nitride nanosheets (BNNS) have been regarded as promising fillers to fabricate polymer matrix composites. However, so far an efficient approach to prepare ultrahigh-aspect-ratio BNNS with large lateral size while maintaining an atomically thin nature is still lacking, seriously restricting further improvement of the thermal conductivity for BNNS/polymer composites. Here, a rapid and high-yield method based on a microfluidization technique is developed to obtain exfoliated BNNS with a record high aspect ratio of ≈1500 and a low degree of defects. A foldable and electrically insulating film made of such a BNNS and poly(vinyl alcohol) (PVA) matrix through filtration exhibits an in-plane thermal conductivity of 67.6 W m K at a BNNS loading of 83 wt %, leading to a record high value of thermal conductivity enhancement (≈35 500). The composite film then acts as a heat spreader for heat dissipation of high-power LED modules and shows superior cooling efficiency compared to commercial flexible copper clad laminate. Our findings provide a practical route to produce electrically insulating polymer composites with high thermal conductivity for thermal management applications in modern electronic devices.
集成电路和电子设备的快速发展，对高导热且电绝缘的复合材料产生了强烈需求，以有效解决设备运行过程中的“热点”问题。基于这些考虑，六方氮化硼纳米片（BNNS）被视为制备聚合物基复合材料的有前途的填料。然而，到目前为止，仍然缺乏一种有效的方法来制备具有大横向尺寸且保持原子级薄特性的超高纵横比BNNS，这严重限制了BNNS/聚合物复合材料热导率的进一步提高。在此，开发了一种基于微流化技术的快速高产方法，以获得具有创纪录的≈1500高纵横比和低缺陷度的剥离BNNS。通过过滤由这种BNNS和聚乙烯醇（PVA）基体制成的可折叠电绝缘薄膜，在BNNS负载量为83 wt%时，面内热导率为67.6 W m⁻¹ K⁻¹，导致热导率增强达到创纪录的高值（≈35500）。该复合薄膜随后用作高功率LED模块散热的热扩散器，与商用挠性覆铜层压板相比，显示出卓越的冷却效率。我们的研究结果为生产用于现代电子设备热管理应用的高导热电绝缘聚合物复合材料提供了一条实用途径。
