Enhanced thermally conductive and dielectrical properties of EP/Co@GNP composites: A strategy via constructing hybrid filler networks using magnetic field-aided orientation

In this work, cobalt (Co) nanoparticles were successfully deposited in situ on graphene nanosheets (GNPs) via electroless plating, and epoxy (EP) resin/Co@GNP heterostructure composites were prepared by a magnetic field-aided solution blending technique. Effects of Co@GNP content and magnetic orientation on EP/Co@GNP composites' dielectric, thermally and electrically conductive, and thermomechanical properties were extensively investigated. Our findings showed it was the synergistic effect of the "point-surface" hybrid filler and magnetic orientation that jointly led to the formation of complicated heterogeneous network, which significantly improved thermally, electrically conductive and thermomechanical properties. Infrared thermal imaging (ITI) together with SEM cross-sectional morphological observations substantiated that the effective bridging of magnetically responsive Co@GNP under magnetic field further improved the heterogeneous network. Excellent thermal conductivity and dielectrical properties of the resultant EP/Co@GNP composites provided a facile way of obtaining high performance thermally conductive materials via magnetic orientation method.