Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
Soft Matter. 2019 Jan 30;15(5):860-869. doi: 10.1039/c8sm02317d.
We introduce an accurate and efficient method for characterizing surface wetting and interfacial properties, such as the contact angle made by a liquid droplet on a solid surface, and the vapor-liquid surface tension of a fluid. The method makes use of molecular simulations in conjunction with the indirect umbrella sampling technique to systematically wet the surface and estimate the corresponding free energy. To illustrate the method, we study the wetting of a family of Lennard-Jones surfaces by water. For surfaces with a wide range of attractions for water, we estimate contact angles using our method, and compare them with contact angles obtained using droplet shapes. Notably, our method is able to capture the transition from partial to complete wetting as surface-water attractions are increased. Moreover, the method is straightforward to implement and is computationally efficient, providing accurate contact angle estimates in roughly 5 nanoseconds of simulation time.
我们介绍了一种精确而高效的方法来描述表面润湿性和界面性质，例如液滴在固体表面形成的接触角，以及流体的汽-液表面张力。该方法利用分子模拟结合间接伞状采样技术来系统地润湿表面并估计相应的自由能。为了说明该方法，我们研究了一系列 Lennard-Jones 表面被水润湿的情况。对于具有广泛水吸引力的表面，我们使用我们的方法估计接触角，并将其与使用液滴形状获得的接触角进行比较。值得注意的是，我们的方法能够捕捉到随着表面-水吸引力的增加，从部分润湿到完全润湿的转变。此外，该方法易于实现且计算效率高，在大约 5 纳秒的模拟时间内就能提供准确的接触角估计。
