四川大学吴凯团队报道了热界面材料权衡的探索——聚合物-填料界面对导热性和触变性的影响。相关研究成果于2024年3月18日发表在国际知名学术期刊《中国高分子科学杂志》。

在热界面材料（TIMs）中至关重要的固体-固体界面的有效热传输，需要最佳的触变性和高导热性。填料表面改性是TIM制造的一个基本方面，在影响这些性能方面的作用尚不完全清楚。

该研究采用硅烷偶联剂（SCA）对氧化铝进行改性，将实验方法与分子动力学模拟相结合，以阐明界面对聚二甲基硅氧烷（PDMS）基TIMs触变性和导热性的影响。研究结果表明，不同的SCAs同时改变了界面结合能和过渡层厚度。界面结合能限制了界面附近的大分子节段弛豫，阻碍了所需的触变性和结合线厚度。

相反，界面处的过渡层厚度积极影响热导率，促进聚合物和填料之间的声子传输。因此，选择最佳SCA能够在相互冲突的高导热率和最小结合线厚度目标之间实现平衡，在40 psi下实现仅2.45-4.29 K·mm²·W^-1的低界面热阻。

附：英文原文

Title: Exploring Trade-offs in Thermal Interface Materials: The Impact of Polymer-Filler Interfaces on Thermal Conductivity and Thixotropy

Author: Bin Zhang, Zheng-Li Dou, Yong-Zheng Zhang, Qiang Fu, Kai Wu

Issue&Volume: 2024-03-18

Abstract: Effective thermal transport across solid-solid interfaces, essential in thermal interface materials (TIMs), necessitates both optimal thixotropy and high thermal conductivity. The role of filler surface modification, a fundamental aspect of TIM fabrication, in influencing these properties is not fully understood. This study employs the use of a silane coupling agent (SCA) to modify alumina, integrating experimental approaches with molecular dynamics simulations, to elucidate the interface effects on thixotropy and thermal conductivity in polydimethylsiloxane (PDMS)-based TIMs. Our findings reveal that varying SCAs modify both interface binding energy and transition layer thickness. The interface binding energy restricts macromolecular segmental relaxation near the interface, hindering desirable thixotropy and bond line thickness. Conversely, the transition layer thickness at the interface positively influences thermal conductivity, facilitating phonon transport between the polymer and filler. Consequently, selecting an optimal SCA enables a balance between traditionally conflicting goals of high thermal conductivity and minimal bond line thickness, achieving an impressively low interface thermal resistance of just 2.454.29 K·mm2·W1 at 40 psi.

DOI: 10.1007/s10118-024-3101-0

Source: https://www.cjps.org/en/article/doi/10.1007/s10118-024-3101-0/