Advanced thermal interface materials based on ultra-thin and ultra-strong metal-gel

Abstract Liquid metal-based thermal interface materials offer exceptional thermal conductivity and conformability, yet their low strength and stabilities remain huge challenges, which largely limits their applications under working conditions of dynamic loading. Here, we utilize an ultrathin nanofiber polymer film as a structural scaffold, which features a robust network essential for effectively confining liquid metal, resulting in unique interpenetrating metal-gel. Surface modification of polymer film with sputtered metals enhances compatibility, enabling uniform infiltration and stabilization of liquid metal. The obtained metal-gels exhibit a remarkable tensile strength of 117 MPa, the highest reported for thermal interface materials, while maintaining good flexibility. They can be fabricated as ultrathin films (≤ 2 µm), delivering an ultralow bond line thickness and interfacial thermal resistance (7.7 mm²·K·W⁻¹). With impressive stability against pressure, folding, solvent exposure, and cooling cycling, this work overcomes key reliability issues of liquid metal, offering promise for advanced cooling applications.