Molecular Dynamics Investigation Of Thermal Properties On Boron Nitride Nano-materials

Low dimensional nanomaterials have attracted much attention due to their excellent properties in many aspects.Two dimensional materials have become the focus of science because of their unique transport properties.Graphene has attracted much attention due to its excellent electrical,mechanical and thermal properties,and has been widely used in sensors,nano electronic devices and other fields,medical and other fields.However,graphene can not be directly applied to heat dissipation of micro nano electronic devices due to its high conductivity.Therefore,boron nitride has attracted more and more attention due to its insulation characteristics and high thermal conductivity.Boron nitride nanomaterials have outstanding thermal properties,unique physical and chemical properties.The structure of boron nitride nanomaterial is similar to graphene.Compared with graphene,the research on BN started late,and the research on thermal conductivity is relatively few.It is difficult to get consistent results for different experimental methods and theoretical parameters.The thermal conductivity of boron nitride is influenced by its own structure and various environmental factors,the effect of size,temperature and chirality on the thermal conductivity of BN nanomaterials is still unclear.In this paper,non-equilibrium molecular dynamics(NEMD)method is used to simulate the thermal properties of BN nanomaterials under the influence of different factors.The thermal properties of single-walled boron nitride nanotubes(BNNTs)and single-layer and multi-layer boron nitride nanosheets(BNNRs)were calculated.The effects of the thermal conductivity with tube structure,temperature,length,diameter and chirality of BN nanotubes were detailed analyzed.These results are of great significance for characterizing the thermal transport properties of BN nanotube based nanoscale thermal conductive modules.The results show that strain can control the thermal conductivity of nano materials.Compared with other means,strain is one of the most easy to implement.However,there are few literatures about the effect of strain on the thermal conductivity of boron nitride nanomaterials.The mechanism of strain on the thermal conductivity of boron nitride nanomaterials is still unclear,which makes the effective control of thermal conductivity of nano devices difficult to achieve.The mechanism of thermal conductivity of BN nanomaterials under strain was systematically analyzed.The effects of tensile,compressive and tensile strains on the thermal properties of BN nanotubes and single-layer and multi-layer BN nanosheets were studied.The research on multilayer BN nanomaterials mostly focuses on the electrical properties,but little on its thermal conductivity,which will greatly hinder its popularization and application.In this paper,the change of thermal conductivity of multilayer boron nitride under the influence of the number of layers,temperature and other factors,as well as the change rule of thermal conductivity on the strain effect are studied,which provides a direction for the active control of the thermal conductivity of multilayer boron nitride in the future practical application,and shows the possibility of strain engineering on the thermal properties of boron nitride nanomaterials.