Thermal Conductivity of Single-Wall Carbon Nanotubes

Despite the significant amount of research on single-wall carbon nanotubes, their thermal conductivity has not been well established. To date only one experimental thermal conductivity measurement has been reported for these molecules around room temperature, with large uncertainty in the thermal conductivity values. Existing theoretical predictions based on molecular dynamics simulation range from several hundred to 6600 W/m-K. In an attempt to clarify the order-of magnitude discrepancy in the literature, this paper utilizes molecular dynamics simulation to systematically examine the thermal conductivity of several (10, 10) single-wall carbon nanotubes as a function of length, temperature, boundary conditions and molecular dynamics simulation methodology. The present results indicate that thermal conductivity ranges from about 30 – 300 W/m-K depending on the various simulation conditions. The results are unconverged and keep increasing at the longest tube length, 40 nm. Agreement with the majority of literature data is achieved for the tube lengths treated here. Discrepancies in thermal conductivity magnitude with experimental data are primarily attributed to length effects, although simulation methodology, stress, and intermolecular potential may also play a role. Quantum correction of the calculated results reveals thermal conductivity temperature dependence in qualitative agreement with experimental data.