Theoretical Model And Simulation For Thermal Transport At The Cross-interface Of Boron Nitride Nanoribbons And Nanotubes

Recent years,as electronic devices have become smaller,the power density significantly increased.The requirements for heat dissipation become higher and higher.Due to their superior thermal transport properties,nanomaterials are generally mixed with polymers or compressed into a sheet to strengthen heat dissipation.However,nanomaterials may stack on each other and form cross-interfaces,which will significantly reduce the thermal conductivity.Therefore,the research and optimization on thermal transport at the cross-interfaces will do help to the improvement of heat dissipation.In terms of theory,the cross-interface model is derived based on the differential equation of thermal transport.It clarifies the basic mechanism of two-dimensional thermal transport at the cross-interface.From the relational expression,it is figured out that the factor ? has important influence on the thermal transport besides the thermal resistance inside and between the materials,which is found to be determined by two dimensionless.One is the ratio of the internal thermal resistance of the material to the thermal resistance between the materials.The other is the relative difference between the internal thermal resistances of the materials forming the cross-interface.In this way,new methods to optimize the thermal transport at the cross-interface are proposed.In terms of simulation,the thermal transport at the cross-interface formed by boron nitride nanoribbons and nanotubes are investigated as an example through non-equilibrium molecular dynamics simulations.The applicability of theoretical model at the nanoscale is discussed.At the nanoribbon cross-interface,the effect of vacancy on thermal transport at the cross-interface is investigated by combining theoretical model and simulation method.As for nanotube cross-interface,it is found that the interfacial thermal conductance varies with overlapped length.The phenomenon is explained by calculating the phonon density of states in boron nitride nanotube.In this work,the thermal transport at the nano cross-interface is explored by combining theory and molecular dynamics simulation.The corresponding mechanism and influencing factors are also investigated.It is believed that the research will deepen the understanding of the interfacial thermal transport and contribute to guiding the applications of nanomaterials in thermal management.