Paving 3D interconnected Cring-C3N4@rGO skeleton for polymer composites with efficient thermal management performance yet high electrical insulation

Polymer-based thermal interface materials (TIMs) with good electrical insulation property is essential in the thermal management of microelectronic devices. A common approach to increasing the polymer's low intrinsic thermal conductivity is to introduce thermally conductive fillers. In most cases, those fillers are also electrically conductive, which destroys the origin electrical insulation property. In this work, we develop a novel heterogeneous two-dimensional hybrid filler by assembling circular carbon nitride (Cring-C3N4) and graphene oxide (GO), aiming to bring the insulation property via Cring-C3N4. With an ordered 3D interconnected structure, the assembled filler shows enlarged sheet size and compact sheet stacking, which facilitates heat conduction. Additionally, the adopted ice-templated method further arranges the filler with the largest thermal conductivity reaching 4.12 W/mK. Meanwhile, it also shows a lower electrical conductivity of 3.6 × 10−7 S/m, meeting most electrical insulation required occasions. Practical heat dissipation performance tests reveal that both larger temperature change rate and maximum attainable temperature are observed for ice-templated treated composite, indicating the reduced thermal contact resistance (TCR) is responsible for the overall improved heat conduction process. This viewpoint is also supported by the practical application of the material functioning as TIMs from both experimental and simulative aspects.