Department of Chemical Engineering, City College of City University of New York, New York, New York 10031, USA.
Department of Physics and The Benjamin Levich Institute for Physico-chemical Hydrodynamics, City College of City University of New York, New York, New York 10031, USA.
J Chem Phys. 2014 Jan 7;140(1):014904. doi: 10.1063/1.4849135.
Nanoparticles with different surface morphologies that straddle the interface between two immiscible liquids are studied via molecular dynamics simulations. The methodology employed allows us to compute the interfacial free energy at different angular orientations of the nanoparticle. Due to their atomistic nature, the studied nanoparticles present both microscale and macroscale geometrical features and cannot be accurately modeled as a perfectly smooth body (e.g., spheres and cylinders). Under certain physical conditions, microscale features can produce free energy barriers that are much larger than the thermal energy of the surrounding media. The presence of these energy barriers can effectively "lock" the particle at specific angular orientations with respect to the liquid-liquid interface. This work provides new insights on the rotational dynamics of Brownian particles at liquid interfaces and suggests possible strategies to exploit the effects of microscale features with given geometric characteristics.
通过分子动力学模拟研究了跨越两种不混溶液体界面的具有不同表面形态的纳米粒子。所采用的方法使我们能够计算纳米粒子在不同角向位置的界面自由能。由于其原子性质，所研究的纳米粒子具有微观和宏观几何特征，不能准确地建模为完美光滑的物体（例如，球体和圆柱体）。在某些物理条件下，微观特征会产生比周围介质的热能大得多的自由能势垒。这些能垒的存在可以有效地将粒子“锁定”在相对于液-液界面的特定角向位置。这项工作提供了关于布朗粒子在液体界面上的旋转动力学的新见解，并提出了利用具有给定几何特征的微观特征的影响的可能策略。
