Low Contact Thermal Resistance without Packaging Pressure in Highly Thermally Conductive Interface Materials Enabled by Polysulfide Vitrimer.

Ye, Neng; Lu, Zhaoyu; Yang, Junzhe; Wang, Junyan; Gao, Yangyang; Li, Jingchao; Lu, Yonglai · Nano Lett · 2025

basic_science · Level V

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Abstract

Thermal interface materials (TIMs) are essential for enhancing interfacial heat transfer, yet achieving both high through-plane thermal conductivity (κ<sub>⊥</sub>) and structural conformability remains difficult. This study introduces a vitrimer-based TIM using a diglycidyl-ether end-capped liquid polysulfide prepolymer (EPS), where stress relaxation from dynamic covalent bonds improves interfacial contact. A vertically aligned graphite composite (VAGC) with high κ<sub>⊥</sub> (15.5 W m<sup>-1</sup> K<sup>-1</sup>) was fabricated via a combined hot-pressing and "stacking-welding" method. Driven by unstable dynamics from a reversible topological network and high surface free energy of thermodynamic properties, VAGC exhibits spontaneous contact behavior. Under zero pressure, the contact thermal resistance drops sharply at 80-100 °C and reaches 16.4 mm<sup>2</sup> K W<sup>-1</sup>, while the effective thermal conductivity of VAGC reaches 14.4 W m<sup>-1</sup> K<sup>-1</sup>. It is believed that the novel EPS vitrimer offers a promising polymer matrix for advanced TIMs.