石墨烯/聚酰亚胺复合膜热导率的分子动力学模拟

摘要

Graphitized polyimide strips act as bridges between graphene nanoribbons to form macro-scale graphitized graphene/ polyimide films.The effect of the sizes of the two components was investigated by non-equilibrium molecular dynamics simulation using the optimized Tersoff molecular force field.Results indicate that the thermal conductivity of the graphene nanoribbon increases almost linearly with length for lengths below 800 nm,but increases as a power function and converges to about 4 300 W/(m · K) above this.The heat conduction between graphene ribbons in the graphitized graphene/polyimide films is improved by increasing the number or width of the graphitized polyimide strips,but is lowered by increasing their length.%石墨化聚酰亚胺条带可作为连接石墨烯的桥梁,形成大尺度石墨烯复合薄膜.采用opt-Tersoff分子力场和非平衡分子动力学方法,计算研究了石墨烯和石墨烯/聚酰亚胺复合膜热导率的尺寸效应.结果发现,石墨烯的热导率与模型的长度相关,增加聚酰亚胺条带的数目或宽度可提高石墨烯/聚酰亚胺复合膜的导热性能,而增加聚酰亚胺条带的长度作用不大.另外,计算了声子态密度用于解释复合膜结构引起的热导率差异.