Three-dimensional network constructed by vertically oriented multilayer graphene and SiC nanowires for improving thermal conductivity and operating safety of epoxy composites with ultralow loading

The oriented graphene could construct an effective heat transfer path in composites with low filler loading. However, electrical conductivity and hygroscopicity caused by functionalized graphene has been ignored, which would decay the lifetime of power devices with the composites as thermal managing materials. In this work, SiC nanowires with high thermal conductivity and hydrophobicity were introduced into vertically oriented multilayer graphene in epoxy resin, constructing an effectively thermally conductive structure. In the structure, multilayer graphene coated with magnetic iron oxide particles responded to external magnetic field, which dramatically reduced the multilayer graphene loading in epoxy resin. When the fillers were rearranged by the magnetic field, the thermal conductivity of the composites reached 0.708 W/(mK), an enhancement of 311.6% compared to epoxy resin. Furthermore, SiC nanowires also damped the electrical conductivity (1.54 × 10−13 S/cm) and hygroscopicity of epoxy composites. The design made it possible for the composites to be applied to electronic packaging field.