Jung Jiyoung, Jeong Seung Hee, Hjort Klas, Ryu Seunghwa
Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.
Soft Matter. 2020 Jul 7;16(25):5840-5847. doi: 10.1039/d0sm00279h. Epub 2020 May 28.
For the facile use of liquid metal composites (LMCs) for soft, stretchable and thermal systems, it is crucial to understand and predict the thermal conductivity of the composites as a function of liquid metal (LM) volume fraction and applied strain. In this study, we investigated the effective thermal conductivity of LMCs based on various mean-field homogenization frameworks including Eshelby, Mori-Tanaka, differential and double inclusion methods. The double inclusion model turned out to make the prediction closest to the experimental results in a wide range of LM volume fractions. Interestingly, we found that the theoretical models based on the assumption of ideal LM dispersion and zero interfacial resistance underestimated the thermal conductivity compared to the experimental results in a low volume fraction regime. By considering the accompanied variations in the LM inclusion's aspect ratios under a typical size distribution of inclusions (∼μm), the change of effective thermal conductivity was predicted under a uniaxial 300% tensile strain. Our study will deepen the understanding of the thermal properties of LMCs and support the designs of stretchable thermal interfaces and packaging with LMCs in the future.
为了便于将液态金属复合材料（LMC）用于柔软、可拉伸的热系统，了解并预测复合材料的热导率随液态金属（LM）体积分数和施加应变的变化至关重要。在本研究中，我们基于包括埃舍尔比、森田、微分和双夹杂方法在内的各种平均场均匀化框架，研究了LMC的有效热导率。结果表明，在较宽的LM体积分数范围内，双夹杂模型的预测结果与实验结果最为接近。有趣的是，我们发现，在低体积分数区域，基于理想LM分散和零界面电阻假设的理论模型低估了热导率。通过考虑在典型夹杂尺寸分布（~μm）下LM夹杂纵横比的伴随变化，预测了在300%单轴拉伸应变下有效热导率的变化。我们的研究将加深对LMC热性能的理解，并为未来使用LMC设计可拉伸热界面和封装提供支持。
