Influence from the types of surface functional groups of RGO on the performances of thermal interface materials

RGO nanosheets-modified epoxy resin (ER) is a major research interest because of the high thermal performance of the resulting thermal interface materials (TIMs). In this study, the attention is focused on the influences from the types of functional groups of the RGO nanosheets on the obtained thermal conductivity. Among all the types of functional groups, the carboxyl group is found to play the most important role to enhance the phonon transport at the interface between the graphene basal plane and ER, which is proven by the obtained thermal conductivity and calculated thermal boundary resistance. A close chemical contact between the graphene and ER is one of the key factors in the resulting high thermal conductivity. Moreover, the formed chemical bond based on the carboxyl group from the RGO and hydroxyl (epoxy) group from the ER also exerts a positive influence on the resulting mechanical performance, which endows a satisfactory ultimate strength and stretch limits to the as-prepared TIMs. The findings of this study reveal the core factors which determine the obtained performances of the graphene-assisted ER, providing a path to further enhance the thermal and mechanical properties of the TIMs for practical application.