Sandwich-structured PVA/rGO films from self-construction with high thermal conductivity and electrical insulation

Highly thermally conductive polymer composites are desirable for the thermal management of modern electronic devices. Although the thermal conductivity issue has been improved effectively with many methods, it always fails in maintaining the electrical insulation performance at the same time, which has become another great challenge. Here the sandwich-structured PVA/PVA-rGO/PVA (recorded as PVA/rGO) composite films simultaneously owning high thermal conductivity, excellent electrical insulation and outstanding flexibility were designed and prepared through self-construction strategy. The obtained results show that the prepared composite films achieved a high in-plane thermal conductivity of 4.00 W m −1  K −1 with only 5 wt% rGO loading, which was about 970% higher than that of pure PVA (0.413 W m −1  K −1 ). The high thermal conductivity is attributed to the formation of the homogeneous intermediate layer of PVA-rGO. In addition, the low filler loading makes the composite film remain excellent mechanical flexibility, and the PVA in the upper and lower layers of the composite film keeps good electrical insulation (volume resistivity beyond 10 9  Ω cm). The prepared composite films not only have great potential applications in the field of thermal management and flexible electronic devices but also have the possibility to conduct the mass production of polymer composites.