Han Shida, Ji Yuan, Zhang Qi, Wu Hong, Guo Shaoyun, Qiu Jianhui, Zhang Fengshun
The State Key Laboratory of Polymer Materials Engineering, Sichuan Provincial Engineering Laboratory of Plastic/Rubber Complex Processing Technology, Polymer Research Institute of Sichuan University, Chengdu, 610065, People's Republic of China.
Department of Mechanical Engineering, Faculty of Systems Science and Technology, Akita Prefectural University, 015-0055, Akita, Japan.
Nanomicro Lett. 2023 Jun 7;15(1):146. doi: 10.1007/s40820-023-01119-0.
As the miniaturization of electronic devices and complication of electronic packaging, there are growing demands for thermal interfacial materials with enhanced thermal conductivity and the capability to direct the heat toward heat sink for highly efficient heat dissipation. Pitch-based carbon fiber (CF) with ultrahigh axial thermal conductivity and aspect ratios exhibits great potential for developing thermally conductive composites as TIMs. However, it is still hard to fabricate composites with aligned carbon fiber in a general approach to fully utilize its excellent axial thermal conductivity in specific direction. Here, three types of CF scaffolds with different oriented structure were developed via magnetic field-assisted Tetris-style stacking and carbonization process. By regulating the magnetic field direction and initial stacking density, the self-supporting CF scaffolds with horizontally aligned (HCS), diagonally aligned and vertically aligned (VCS) fibers were constructed. After embedding the polydimethylsiloxane (PDMS), the three composites exhibited unique heat transfer properties, and the HCS/PDMS and VCS/PDMS composites presented a high thermal conductivity of 42.18 and 45.01 W m K in fiber alignment direction, respectively, which were about 209 and 224 times higher than that of PDMS. The excellent thermal conductivity is mainly ascribed that the oriented CF scaffolds construct effective phonon transport pathway in the matrix. In addition, fishbone-shaped CF scaffold was also produced by multiple stacking and carbonization process, and the prepared composites exhibited a controlled heat transfer path, which can allow more versatility in the design of thermal management system.
随着电子设备的小型化和电子封装的复杂化，对具有增强热导率以及能够将热量导向散热器以实现高效散热的热界面材料的需求日益增长。具有超高轴向热导率和长径比的沥青基碳纤维（CF）在开发作为热界面材料的导热复合材料方面具有巨大潜力。然而，采用常规方法制备具有取向碳纤维的复合材料仍然困难，难以充分利用其在特定方向上优异的轴向热导率。在此，通过磁场辅助的俄罗斯方块式堆叠和碳化工艺开发了三种具有不同取向结构的CF支架。通过调节磁场方向和初始堆叠密度，构建了具有水平取向（HCS）、对角取向和垂直取向（VCS）纤维的自支撑CF支架。在嵌入聚二甲基硅氧烷（PDMS）后，这三种复合材料表现出独特的传热性能，HCS/PDMS和VCS/PDMS复合材料在纤维取向方向上分别呈现出42.18和45.01 W m⁻¹K⁻¹的高导热率，分别比PDMS高约209倍和224倍。优异的热导率主要归因于取向CF支架在基体中构建了有效的声子传输路径。此外，通过多次堆叠和碳化工艺还制备了鱼骨状CF支架，所制备的复合材料表现出可控的传热路径，这在热管理系统设计中具有更高的通用性。
