Thermal and electrical conductivity control in hybrid composites with graphene and boron nitride fillers

We report on the thermal and electrical properties of hybrid epoxy composites\nwith graphene and boron nitride fillers. The thicknesses, lateral dimensions,\nand aspect ratios of each filler material were intentionally selected for\ngeometric similarity to one another, in contrast to prior studies that utilized\ndissimilar filler geometries to achieve a "synergistic" effect. We demonstrate\nthat the electrically-conductive graphene and electrically-insulating boron\nnitride fillers allow one to effectively engineer the thermal and electrical\nconductivities of their resulting composites. By varying the constituent\nfraction of boron nitride to graphene in a composite with ~44% total filler\nloading, one can tune the thermal conductivity enhancement from a factor of x15\nto x35 and increase the electrical conductivity by many orders of magnitude.\nThe obtained results are important for the development of next-generation\nthermal interface materials with controllable electrical properties necessary\nfor applications requiring either electrical grounding or insulation.\n