Thermal transport across hard–soft interfaces is critical to many modern applications, such as composite materials, thermal management in microelectronics, solar–thermal phase transition, and nanoparticle-assisted hyperthermia therapeutics. In this study, we use equilibrium molecular dynamics (EMD) simulations combined with the Green–Kubo method to study how molecularly heterogeneous structures of the self-assembled monolayer (SAM) affect the thermal transport across the interfaces between the SAM-functionalized gold and organic liquids (hexylamine, propylamine and hexane). We focus on a practically synthesizable heterogeneous SAM featuring alternating short and long molecular chains. Such a structure is found to improve the thermal conductance across the hard–soft interface by 46–68% compared to a homogeneous nonpolar SAM. Through a series of further simulations and analyses, it is found that the root reason for this enhancement is the penetration of the liquid molecules into the spaces between the long SAM molecule chains, which increase the effective contact area. Such an effect is similar to the fins used in macroscopic heat exchanger. This “molecular fin” structure from the heterogeneous SAM studied in this work provides a new general route for enhancing thermal transport across hard–soft material interfaces.

中文翻译：

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异质自组装单分子层的分子鳍效应增强了跨软硬界面的热传导

跨软-软界面的热传输对于许多现代应用至关重要，例如复合材料，微电子学中的热管理，太阳-热相变和纳米粒子辅助的高温疗法。在这项研究中，我们将平衡分子动力学（EMD）模拟与Green-Kubo方法结合使用，研究自组装单分子层（SAM）的分子异质结构如何影响通过SAM功能化的金与有机物之间的界面的热传输。液体（己胺，丙胺和己烷）。我们专注于具有短链和长链交替特征的可合成的异质SAM。与同质非极性SAM相比，这种结构可将整个软硬界面的导热系数提高46％至68％。通过一系列进一步的模拟和分析，发现这种增强的根本原因是液体分子渗透到长SAM分子链之间的空间中，从而增加了有效接触面积。这种效果类似于宏观热交换器中使用的散热片。这项工作中研究的异质SAM中的“分子鳍”结构为增强跨软硬材料界面的热传递提供了一条新的通用途径。