Graphene/hexagonal boron nitride hetero-fillers for enhanced interfacial thermal conductance in polymer nanocomposites

Paraffin-based polymer nanocomposites, reinforced with thermally conductive nanofillers, have been widely utilized as cost-effective thermal interface materials (TIMs) for efficient heat management in electronic systems. In this study, we delve in new paraffin nanocomposites reinforced with graphene/h-BN (GBN) heterostructures for improving their thermal performance. Based on intensive reverse non-equilibrium molecular dynamics (RNEMD) simulations, we showed that the GBN-paraffin interfacial thermal conductance (ITC) is improved through modifications of GBN nanofillers with three functional groups – methyl (-CH₃), hydroxyl (-OH) and carbon-doping (C-doping). From detailed mean squared displacement (MSD) and vibrational density of states (VDOS) analyses, we discovered that the -CH₃ functional group is the most effective strategy because it causes stronger phonon interactions and facilitates greater phonon coupling at the interface. Furthermore, effective medium theory (EMT) calculations unveil the intricate interplay between filler size and volume fraction in maximizing thermal conductivity. These findings provide valuable material design guidelines and insights into leveraging GBN as a high-efficiency thermal conductive filler for advanced thermal management applications.