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

Theapplication of graphene/epoxy composites in microelectronicdevices 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 thermalconductivity of nanocomposites at the nanoscale remains unclear. Here,several common methods are used to decrease graphene-epoxyITR 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 conductivityslightly. Then, nanocomposites are simplified as three representativevolume element models: the non-contacted model, the stacked model,and the intersected model. For the non-contacted model, the graphene-epoxyinterfacial heat transfer coefficient is increased by 303% by functionalizingthe graphene edge with amino groups, and the thermal conductivityis improved by 45.3%. For the stacked model, the graphene-grapheneITR is decreased by 220% when vacancy defects are constructed in thestacking region, and the thermal conductivity is improved by 130%.The intersected model's heat transfer coefficient in the intersectingnode is increased by 590% by connecting two graphene sheets by covalentinteractions, and the thermal conductivity is improved by 590%. Finally,the stacked and intersected models are combined to construct the graphene/epoxynanocomposites with a graphene network, and the thermal conductivitycan be adjusted by changing the vacancy coverage rate.