Atomistic molecular dynamic simulations of the thermal transport across h-BN/cellulose nanocrystal interface

Abstract

Owing to their high intrinsic thermal conductivity (~2.0 W/mK), cellulose nanocrystals (CNCs) have a high potential for use as thermal management materials in modern electronics. The incorporation of a nanofiller with a high thermal conductivity, such as h-boron nitride (h-BN) and graphene (Gr), is a common approach to improve the thermal properties. However, the thermal transport across the filler–matrix interface is not well understood considering the existence of amphiphilic surfaces in the CNCs. In this study, the interfacial thermal conductance (ITC) between the hydrophobic or hydrophilic surfaces of the CNCs and h-BN was systematically investigated using molecular dynamic simulations. The hydrophobic surface exhibited the highest ITC, and the ITC for ordered CNCs was higher than that for the amorphous cellulose. The ITCs of h-BN/CNCs were higher than those of Gr/CNCs. The underlying mechanisms were explained by the interfacial adhesion strength and phonon vibration power spectrum. Additionally, the overall thermal performances of the CNCs/h-BN nanocomposites were investigated through the effective medium theory and simulation results. Although the inherent thermal conductivity of h-BN was lower than that of Gr, because of the dominant effect of the ITC on the heat transfer in the nanocomposites, h-BN with a higher ITC may increase the thermal conductivity of the CNCs more than Gr.