Wilson Blake A, Nielsen Steven O, Randrianalisoa Jaona H, Qin Zhenpeng
Department of Mechanical Engineering, The University of Texas at Dallas, Richardson, Texas 75080, USA.
Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, USA.
J Chem Phys. 2022 Aug 7;157(5):054703. doi: 10.1063/5.0090683.
Plasmonic gold nanoparticles (AuNPs) can convert laser irradiation into thermal energy for a variety of applications. Although heat transfer through the AuNP-water interface is considered an essential part of the plasmonic heating process, there is a lack of mechanistic understanding of how interface curvature and the heating itself impact interfacial heat transfer. Here, we report atomistic molecular dynamics simulations that investigate heat transfer through nanoscale gold-water interfaces. We simulated four nanoscale gold structures under various applied heat flux values to evaluate how gold-water interface curvature and temperature affect the interfacial heat transfer. We also considered a case in which we artificially reduced wetting at the gold surfaces by tuning the gold-water interactions to determine if such a perturbation alters the curvature and temperature dependence of the gold-water interfacial heat transfer. We first confirmed that interfacial heat transfer is particularly important for small particles (diameter ≤10 nm). We found that the thermal interface conductance increases linearly with interface curvature regardless of the gold wettability, while it increases nonlinearly with the applied heat flux under normal wetting and remains constant under reduced wetting. Our analysis suggests the curvature dependence of the interface conductance coincides with changes in interfacial water adsorption, while the temperature dependence may arise from temperature-induced shifts in the distribution of water vibrational states. Our study advances the current understanding of interface thermal conductance for a broad range of applications.
等离子体金纳米颗粒（AuNPs）可将激光辐射转化为热能，用于多种应用。尽管通过AuNP-水界面的热传递被认为是等离子体加热过程的一个重要部分，但对于界面曲率和加热本身如何影响界面热传递，仍缺乏机理上的理解。在此，我们报告了通过纳米级金-水界面研究热传递的原子分子动力学模拟。我们在各种施加的热通量值下模拟了四种纳米级金结构，以评估金-水界面曲率和温度如何影响界面热传递。我们还考虑了一种情况，即通过调整金-水相互作用人为降低金表面的润湿性，以确定这种扰动是否会改变金-水界面热传递的曲率和温度依赖性。我们首先证实，界面热传递对于小颗粒（直径≤10 nm）尤为重要。我们发现，无论金的润湿性如何，热界面电导都随界面曲率线性增加，而在正常润湿下，它随施加的热通量非线性增加，在润湿性降低时保持不变。我们的分析表明，界面电导的曲率依赖性与界面水吸附的变化一致，而温度依赖性可能源于温度引起的水振动状态分布的变化。我们的研究推动了目前对广泛应用中界面热导的理解。
