Abstract Owing to the super thermal conductivity of graphene, graphene/polymer nanocomposites have the potential as thermal management materials in many applications. Previous studies have proved that the defects in the graphene sheets can greatly reduce the thermal conductivity of suspended graphene. However, the effects of defects on the interfacial thermal conductance and thermal conductivity of graphene/epoxy nanocomposites have not been well understood. In this paper, the effect of four common types of defects, i.e., single-vacancy, double-vacancy, Stone-Wales and Multi-vacancy, on the interfacial thermal transport between the epoxy and graphene was systematically investigated by using molecular dynamic simulations. The simulation results showed that the interfacial thermal conductance between graphene-epoxy could be considerably enhanced with the existence of Stone-Wales and Multi-vacancy defects. The underlying mechanism was explicated by using the phonon vibration power spectrum. Additionally, based on the effective medium theory and the simulation results, the effect of defects on the thermal conductivity of graphene/epoxy nanocomposites was investigated concerning different graphene filler sizes and volume fractions. Although the inherent thermal conductivity of embedded graphene may be decreased by its defects, it was possible to increase the thermal conductivity of the nanocomposites when the graphene filler size was smaller than a critical value.

中文翻译：

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缺陷对石墨烯/环氧树脂纳米复合材料热导率的影响

摘要 由于石墨烯的超导热性，石墨烯/聚合物纳米复合材料在许多应用中具有作为热管理材料的潜力。先前的研究证明，石墨烯片中的缺陷可以大大降低悬浮石墨烯的导热系数。然而，缺陷对石墨烯/环氧树脂纳米复合材料的界面热导率和热导率的影响尚未得到很好的理解。在本文中，通过使用分子动力学模拟系统地研究了四种常见类型的缺陷，即单空位、双空位、Stone-Wales 和多空位对环氧树脂和石墨烯之间的界面热传输的影响。模拟结果表明，随着 Stone-Wales 和多空位缺陷的存在，石墨烯-环氧树脂之间的界面热导率可以显着提高。通过使用声子振动功率谱解释了潜在的机制。此外，基于有效介质理论和模拟结果，研究了缺陷对石墨烯/环氧树脂纳米复合材料热导率的影响，涉及不同的石墨烯填料尺寸和体积分数。尽管嵌入石墨烯的固有热导率可能因其缺陷而降低，但当石墨烯填料尺寸小于临界值时，有可能增加纳米复合材料的热导率。通过使用声子振动功率谱解释了潜在的机制。此外，基于有效介质理论和模拟结果，研究了缺陷对石墨烯/环氧树脂纳米复合材料热导率的影响，涉及不同的石墨烯填料尺寸和体积分数。尽管嵌入石墨烯的固有热导率可能因其缺陷而降低，但当石墨烯填料尺寸小于临界值时，有可能增加纳米复合材料的热导率。通过使用声子振动功率谱解释了潜在的机制。此外，基于有效介质理论和模拟结果，研究了缺陷对石墨烯/环氧树脂纳米复合材料热导率的影响，涉及不同的石墨烯填料尺寸和体积分数。虽然嵌入石墨烯的固有热导率可能因其缺陷而降低，但当石墨烯填料尺寸小于临界值时，有可能增加纳米复合材料的热导率。