Thermal Conductivity Enhancement of Graphene/Epoxy Nanocomposites by Reducing Interfacial Thermal Resistance

Abstract

The application of graphene/epoxy composites in microelectronic devices has been greatly limited by interfacial thermal resistance (ITR), which has been widely studied to improve the composites' thermal conductivity. However, the effect of changing ITR on the thermal conductivity of nanocomposites at the nanoscale remains unclear. Here, several common methods are used to decrease graphene–epoxy ITR and graphene–graphene ITR, and the enhanced degree of nanocomposites' thermal conductivity is investigated by molecular dynamics. First, the graphene concentration is proven to influence thermal conductivity slightly. Then, nanocomposites are simplified as three representative volume element models: the non-contacted model, the stacked model, and the intersected model. For the non-contacted model, the graphene–epoxy interfacial heat transfer coefficient is increased by 303% by functionalizing the graphene edge with amino groups, and the thermal conductivity is improved by 45.3%. For the stacked model, the graphene–graphene ITR is decreased by 220% when vacancy defects are constructed in the stacking region, and the thermal conductivity is improved by 130%. The intersected model's heat transfer coefficient in the intersecting node is increased by 590% by connecting two graphene sheets by covalent interactions, and the thermal conductivity is improved by 590%. Finally, the stacked and intersected models are combined to construct the graphene/epoxy nanocomposites with a graphene network, and the thermal conductivity can be adjusted by changing the vacancy coverage rate.