Thermal boundary resistance and thermal conductivity of multiwalled carbon nanotubes

Thermal boundary resistance (Kapitza resistance) and thermal conductivity of multiwalled carbon nanotubes (MWCNTs) are calculated assuming the properties of graphite in the temperature range of $10–100K$. By including the thermal boundary resistance between the MWCNT and the measuring device, calculated thermal conductivity of MWCNT is in very good agreement with the experimental data of Kim et al. [Phys. Rev. Lett. 87, 215502 (2001)], showing that the thermal behavior of MWCNTs is similar to graphite. Thermal conductivity of MWCNT as measured by Kim et al. is smaller than the thermal conductivity of graphite fibers and pyrolytic graphite at low temperatures due to thermal boundary resistance. The intrinsic mean free path of phonons in MWCNTs in the temperature range of $10–100K$ is found to be similar to the mean free path in graphite fibers. Finally, it is shown that the thermal boundary resistance could be one of the main reasons that the thermal conductivity of MWCNT bundles as measured by Kim et al. is lower than the thermal conductivity of a single MWCNT.