Thermal conduction through individual cellulose nanofibers

Cellulose nanofibers (CNF) are abundant biomaterials that have attracted significant attention in the thermal management field for a wide range of applications including flexible heat dissipation materials and thermal insulators. While thermal transport properties of individual CNFs are significant for the fundamental understanding and design of advanced materials, experimental studies of the thermal transport properties of CNFs are limited to bulk scales and thermal measurement on individual CNFs has not been reported to date. We report here the experimental study on the thermal conductivity (κ) of individual CNFs using the well-established thermal bridge method. The κ of individual CNFs is found to be approximately 2.2 (±1.2) W/m K at 300 K, and the temperature dependent data from 40 to 320 K indicate that the phonon transport of CNFs is dominated by boundary scattering. Theoretical simulation results on κ of individual CNFs and cellulose bulk crystal support the experimental results and suggest that intermolecular interaction also impedes the thermal transport.