Boron nitride/expanded graphite heterojunction films for the epoxy composites to enhance the heat dissipation capabilities

The integration and portable development of electronic devices urgently require flexible films with high thermal conductivity and insulation to overcome heat accumulation. The layered heterojunction composite films are prepared by the stacking technique for the first time. The morphology, structure composition and thermal stability of heterojunction films are studied. Compared with pure epoxy resin (EP), the heterojunction film still has good thermal stability at 600°C. At the same time, the plane heat conduction network constructed by the expanded graphite (EG) plane of the heterojunction film enables the film to dissipate heat effectively. In the simulation process of actual heat dissipation, the chip surface temperature can be reduced by 10°C. The thermal conductivity of the heterojunction film is 2.49 Wm⁻¹ K⁻¹ when the mass fraction of boron nitride- γ aminopropyl triethoxysilane (BN-KH550) is 50 wt%. Compared with pure epoxy resin, the thermal conductivity is increased by 1464%. The boron nitride (BN) surface resistance of the heterojunction film is large, which can isolate the conductive path of the EG layer and provide effective electrical insulation.