Sudhindra Sriharsha, Rashvand Farnia, Wright Dylan, Barani Zahra, Drozdov Aleksey D, Baraghani Saba, Backes Claudia, Kargar Fariborz, Balandin Alexander A
Phonon Optimized Engineered Materials Center, University of California, Riverside, California 92521, United States.
Department of Electrical and Computer Engineering, Bourns College of Engineering, University of California, Riverside, California 92521, United States.
ACS Appl Mater Interfaces. 2021 Nov 10;13(44):53073-53082. doi: 10.1021/acsami.1c15346. Epub 2021 Oct 27.
We report on the investigation of thermal transport in noncured silicone composites with graphene fillers of different lateral dimensions. Graphene fillers are comprised of few-layer graphene flakes with lateral sizes in the range from 400 to 1200 nm and the number of atomic planes from 1 to ∼100. The distribution of the lateral dimensions and thicknesses of graphene fillers has been determined via atomic force microscopy statistics. It was found that in the examined range of the lateral dimensions, the thermal conductivity of the composites increases with increasing size of the graphene fillers. The observed difference in thermal properties can be related to the average phonon mean free path in graphene, which has been estimated to be around ∼800 nm at room temperature. The thermal contact resistance of composites with graphene fillers of 1200 nm lateral dimensions was also smaller than that of composites with graphene fillers of 400 nm lateral dimensions. The effects of the filler loading fraction and the filler size on the thermal conductivity of the composites were rationalized within the Kanari model. The obtained results are important for the optimization of graphene fillers for applications in thermal interface materials for heat removal from high-power-density electronics.
我们报告了对具有不同横向尺寸石墨烯填料的未固化有机硅复合材料中热传输的研究。石墨烯填料由横向尺寸在400至1200纳米范围内且原子层数为1至约100的少层石墨烯薄片组成。通过原子力显微镜统计确定了石墨烯填料的横向尺寸和厚度分布。结果发现，在所研究的横向尺寸范围内，复合材料的热导率随石墨烯填料尺寸的增加而增加。观察到的热性能差异可能与石墨烯中的平均声子平均自由程有关，据估计在室温下约为800纳米左右。横向尺寸为1200纳米的石墨烯填料复合材料的热接触电阻也小于横向尺寸为400纳米的石墨烯填料复合材料的热接触电阻。在卡纳里模型内对填料负载分数和填料尺寸对复合材料热导率的影响进行了合理化分析。所得结果对于优化用于从高功率密度电子设备散热的热界面材料中的石墨烯填料具有重要意义。
