Molecular dynamics is used to investigate the thermocapillary motion of a water nanodroplet suspended in benzene subjected to a constant temperature gradient. This framework lets us identify the average behavior of the fluid particles by revealing their mean evolution. We connect such statistics to the behavior of the temporally evolving nanodroplet, thereby providing a microphysical foundation to existing macroscopic models that rely on the assumption of continuum. It is shown that, despite the significant Brownian effects, the droplet exhibits the macrophysical expected behavior, i.e., it migrates toward the direction of the imposed temperature gradient. Thermophoretic effects are negligible and the functional relationships involved in such a process well resemble those of available analytical results. Additionally, we provide molecular dynamics calculations of the viscosity, thermal conductivity, and interfacial tension of benzene [using the Optimized Potentials for Liquid Simulations—All Atom (OPLSAA) molecular model] and water using the Transferable Intermolecular Potential with 4 Points (TIP4P) model at different temperatures and pressures. These findings will serve as a good reference for future simulations of similar molecular models.

中文翻译：

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使用分子动力学研究纳米液滴的热毛细管迁移

分子动力学用于研究在恒定温度梯度下悬浮在苯中的水纳米滴的热毛细管运动。该框架使我们能够通过揭示流体粒子的平均演化来确定其平均行为。我们将此类统计数据与时间演化的纳米液滴的行为联系起来，从而为依赖于连续体假设的现有宏观模型提供了微观物理基础。结果表明，尽管有显着的布朗效应，但液滴仍表现出宏观物理的预期行为，即，其朝着所施加的温度梯度的方向迁移。热泳效应可以忽略不计，并且这种过程中涉及的功能关系与可用分析结果非常相似。此外，我们提供了分子粘度，导热系数和界面张力的分子动力学计算（使用液体模拟的最佳电位-全原子（OPLSAA）分子模型）和水（使用4点可转移分子间电位（TIP4P）模型）温度和压力。这些发现将为将来类似分子模型的模拟提供良好的参考。