Thermal contact resistance and thermal conductivity of a carbon nanofiber

We have measured the thermal resistance of a 152-nm-diameter carbon nanofiber before and after a platinum layer was deposited on the contacts between the nanofiber and the measurement device. The contact resistance was reduced by the platinum coating for about 9-13% of the total thermal resistance of the nanofiber sample before the platinum coating. At a temperature of 300 K, the axial thermal conductivity of the carbon nanofiber is about three times smaller than that of graphite fibers grown by pyrolysis of natural gas prior to high-temperature heat treatment, and increases with temperature in the temperature range between 150 K and 310 K. The phonon mean free path was found to be about 1.5 nm and approximately temperature-independent. This feature and the absence of a peak in the thermal conductivity curve indicate that phonon-boundary and phonon-defect scattering dominate over phonon-phonon Umklapp scattering for the temperature range.