Design of yield-stress fluids with ultra-low thermal resistance via surface functionalization of aluminum fillers

Thermal resistance at the interface between chips and cooling devices is a major impediment to heat removal, especially in the development of high-power-density AI chips. Yield-stress type thermal interfacial materials are inserted to reduce the thermal resistance between chips and cooling devices, meanwhile avoiding pumping out and significant expansion. However, the trade-off between thermal resistance and yield stress for thermal interfacial materials remains a major obstacle to achieving efficient heat dissipation. Here, we report yield-stress fluids consisting of polydimethylsiloxane, polydimethylsiloxane trimethoxysilane-functionalized aluminum powders, exhibiting an ultra-low thermal resistance (0.019 K cm²/W) and moderate yield stress (84.51 Pa). The surface functionalization of aluminium powders achieves homogeneous distribution at high content (81.5 vol%), and enhances interfacial bonding between aluminium powders and polydimethylsiloxane. A jamming phase diagram is constructed to reflect the critical parameters of the solid–liquid yield transition, and a two-phase model is invoked to explain the regulatory mechanism of the aluminum network. Based on the thixotropy, solid–liquid yield transition and ultra-low thermal resistance, the yield-stress fluids demonstrate exceptional thermal management performance in chip dissipation scenarios. This work provides a new direction for the future evolution of high-efficiency thermal interface materials, which has great transformative potential in advancing thermal management technology.