氢键连接的石墨烯纳米片之间界面传热的分子模拟研究

Thermal Transport Between Graphene Nanosheets Connected Through Hydrogen Bonds

石墨烯的高热导率使其成为导热复合材料中重要的填料,然而填料间的界面热阻极大地阻碍了填料间的热传输。对石墨烯边缘进行官能化可以在石墨烯边缘界面间引入共价键或氢键连接,以取代范德瓦尔斯(Van Der Waals)相互作用连接,从而有望增强界面热传导。该文系统研究了边缘化学吸附—COOH的石墨烯片间界面传热性质,探讨了石墨烯片间距离以及官能化密度对于界面热阻的影响。研究表明,随着两片石墨烯边缘间距减小,边缘化学吸附—COOH的石墨烯片间界面热导逐渐收敛于5×10^8 W/(m^2·K)附近。这相比于H边缘官能化的石墨烯片间界面热导提高了一个数量级。界面热导随着官能化密度的提高显示出非线性单调提升。进一步的研究显示,官能化密度与石墨烯边缘界面间距存在协同效应,官能化密度的增加提高了界面间的相互作用,减小了石墨烯边缘界间距,从而增强了界面热导。该研究结果可为氢键对于石墨烯填料界面传热调控提供重要参考。

The high thermal conductivity of graphene makes it an important filler material for thermally conductive composite materials.However,the interfacial thermal resistance between the fillers greatly hinders the heat transfer between the fillers.The functionalization of the edges of graphene can introduce covalent or hydrogen bonding between the graphene edge interfaces to replace Van Der Waals(VDWs)interaction connections,which is expected to enhance the interfacial thermal conductance.In this paper,the interfacial heat transfer properties of the graphene chemically functionalized with—COOH groups are systematically studied,and the effects of the distance between graphene sheets and the functionalized density on the interface thermal resistance are discussed.The results show that,as the distance between the edges of the two graphene sheets decreases,the interfacial thermal conduction between the interfaces of the functionalized graphene gradually converges to around 5×10^8 W/(m^2·K),which is an order of magnitude higher than that between the H-terminated graphene.The interfacial thermal conduction shows a non-linear monotonous increase with increasing the functionalization density.Further results show that there is a synergistic effect between the functionalized density and the graphene edge interface spacing.Increasing the functionalized density improves the interaction between the interfaces and reduces the interface spacing between the graphene edges,thereby enhancing the interfacial thermal conduction.The results of this paper provide an important reference for the study of effects of hydrogen bonding on the interfacial heat transfer between graphene fillers.