Molecular Dynamics Simulation Of The Thermal Conductivity Of Single-Wall Carbon Nanotubes

The discovery of carbon nanotubes (CNT's) by Iijima in 1991 and subsequent observations of CNT's unique mechanical and electrical properties have captured intensive attention of researchers on this quasi-one-dimensional material. As the dimensions of electronic devices shrink to the micro or nanometer scale, the reliability and the useful lives of most micro-electromechanical systems are dominated by the thermal conduction efficiency. The characteristics of CNT's are similar to those of both diamond and graphite, which have high thermal conductivities. Therefore, CNT's or composites based on CNT's are suggested to be attractive for heat transport in miniature device components for their highly directional heat transfer capability. It has been found that a single-wall carbon nanotube (SWNT) of sufficiently large diameter can be filled with spherical C60 molecules to form a new mixture referred to as a"peapod", with spherical fullerenes representing peas and the CNT representing a pod. It is expected that the thermal characteristic of this new material would be different from those of an unfilled carbon nanotube, and some results have been reported.In this paper, to further investigate the thermal conductivity of this kind of material, argon atoms are filled in a SWNT instead of C60, while (10, 10) and (15, 15) SWNTs with the same length about 5 nm are investigated respectively. Thermal conductivities of them are calculated over a temperature range of 500~1200 K using molecular dynamics (MD) simulations. To compare with the thermal conductivity of pure CNT's and study the effects of filled Ar on the thermal conductivity of CNT's, thermal conductivities of unfilled (10, 10) and (15, 15) SWNTs in the same conditions are also calculated using MD simulation method.It is found that the thermal conductivity of filled (10, 10) or (15, 15) SWNTs, showing qualitatively similar behavior to that of a bare unfilled nanotube, decreases as the temperature increases. Moreover, it is demonstrated that the thermal conductivity of CNT's filled with argon is much higher than that of an empty carbon nanotube at all temperatures. This increase is perhaps attributed to the heat transfer derived from the Ar-nanotube interaction, and the mass transport due to the active movement of the Ar atom in CNT's.