Research On Thermal Conductivity Of Carbon Nanotube Networks By Molecular Dynamics Simulation

Carbon nanotubes(CNTs)and their junctions are building block of carbon based nanodevice and carbon nanotube networks.In recent years,researches on carbon based nanodevice and novel materials based on carbon nanotube networks have attracted a lot of attention.Individual carbon nanotube has superhigh thermal conductivity,thus study on thermal conductivity of carbon nanotube junction and carbon nanotube networks are crucial for thermal management and thermal enhancement..In this study,the thermal conductivities of random CNTs networks are investigated,and the inter-tube thermal conductance and intra-tube axial thermal resistance between the intersecting single-walled,double-walled and three-walled carbon nanotubes are calculated.Moreover,a new hybrid model is proposed to calculate the thermal conductivities of partially sintered randomly oriented carbon nanotube networks.The main contents are as follows:(1)The thermal conductivities of single-walled carbon nanotubes(SWNTs)were calculated by molecular dynamics(MD)simulations,and the effects of wall to wall distance on inter-tube thermal conductance are also discussed.The contact thermal conductance between the two thermal contact points and three thermal contact points under different conditions was also calculated,which provides a prerequisite for the calculation of thermal conductance of the whole carbon nanotube random network.(2)The heat welding of crossed double-walled carbon nanotube(DWNTs)and multi-walled carbon nanotube(MWNTs)are conducted via MD simulations.The inter-tube thermal conductance and intra-tube axial thermal resistance of the junctions DWNTs and MWNTs are calculated by MD simulations,therefore basic conditions are prepared for the prediction of the overall thermal conductivities of sintered randomly oriented CNT networks.(3)The Chalopin model and the Volkov model are compared and a hybrid analysis model are proposed to calculate the thermal conductivities of partially sintered randomly oriented CNT networks.The thermal conductivities of SWCNTs,DWCNTs and MWCNTs networks with different density were calculated,and the mechanism why thermal conductivity of DWNTs and MWNTs networks can be enhanced are explained..