A thermally conductive and insulating epoxy polymer composite with hybrid filler of modified copper nanowires and graphene oxide

Epoxy composites comprising modified graphene oxide and copper nanowires as hybrid fillers were prepared, in which dopamine (DA) is used as modifier for copper nanowires and graphene oxide (GO). Dopamine is easily oxidized to self-polymerize into adherent polydopamine (PDA) coating on all sorts of substrates in alkaline aqueous solution. In this paper, CuNWs@PDA and GO@PDA have been prepared successfully and confirmed by TEM, SEM and XRD, which indicates that the coating layer of PDA is uniformly capped on the copper nanowires and GO nanosheets. Meanwhile, the properties of epoxy composite were obtained by testing the thermal properties, volume resistivity and dielectric constant. The different proportions of hybrid fillers prepared by two modified fillers result in different thermal conductivities and other properties. The experimental results show that the epoxy composites possess higher thermal conductivity for 0.36 W/m K and excellent electrical insulation properties when the proportion of filler CuNWs@PDA:GO@PDA is 7:3. This is mainly attributed to the good interfacial adhesion between CuNWs@PDA/GO@PDA and resin as well as the synergetic effect between CuNWs@PDA and GO@PDA.