Semi-quantitative orientation control of graphite nanoplatelets in GNP/PU nanocomposite via balancing the effects of gravity and micro-flow field and application in manufacturing heat spreader substrate with excellent thermal conductivity

As the huge demand for a multifunctional electronic device with high performance, an important technology in next-generation electronics is thermal management and there are numerous uses for it in enhancing the reliability and sustainable utilization. In this work, a high thermal conductivity substrate based on graphite nanoplatelets (GNPs)/ polyurethane (PU) nanocomposite film is fabricated. The GNPs’ orientation can be semi-quantitative controlled by balancing the effect of gravity and micro-flow field, which results in a thermal conductivity varies from 38.1 W (m·K)^-1 to 19.8 W (m·K)^-1 as the orientation rearrangement. Meanwhile, Interfacial thermal resistance is evaluated by the Effective medium theory (EMT) models, which is about 1.76 × 10^-6 K m²/W to 2.0 × 10^-6 K m²/W at 30 °C. Additionally, the chip fixed to the GNP/PU substrate (38.1 W (m·K)^-1) could work under a lower temperature than the commercial polycarbonate substrate. Our method is a promising strategy for thermal management of next-generation electronics devices.