A graphene nanoflake-based flexible composite phase change material for enhanced heat dissipation in chip cooling

Efficient heat dissipation is a key requirement for stable performance retention and failure prevention of microelectronic components. In practical applications, the interface thermal resistance between the component and the heat dissipation unit affects the heat dissipation effect. Thermal interface materials (TIM) are used to fill the voids at the solid interface between the device and the heat sink to create a thermally conductive path for heat dissipation. Phase change materials (PCMs) are candidates as TIM for next-generation electronic devices due to their excellent latent heat storage. However, some inherent problems of PCMs, such as low thermal conductivity, high solid-state rigidity, and easy leakage, also limit their application in the thermal management of electronic equipment. This study prepared a biomass cotton cloth substrate with a woven structure attached to graphite nanosheets and further constructed a thermally conductive matrix through drying or high-temperature carbonization. Through the composite of thermally conductive matrix and paraffin wax (PW), a flexible phase change thermal interface composite material was obtained. The phase change enthalpy of composite materials is as high as 157.7 J/g. The thermal conductivity of the composite material is 295 % higher than that of pure PW. On its excellent flexibility and structural strength, the composite material can better adapt to the thermal interface, reduce contact thermal resistance, and thus achieve good leakage resistance. The flexible phase-change TIM developed in this study have broad application prospects in the fields of chip heat dissipation and thermal management of wearable electronic devices.