Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada.
J Chem Phys. 2017 Mar 21;146(11):114704. doi: 10.1063/1.4978497.
A novel method to calculate the solid-liquid contact angle is introduced in this study. Using the 3D configuration of a liquid droplet on a solid surface, this method calculates the contact angle along the contact line and provides an angular distribution. Although this method uses the 3D configuration of liquid droplets, it does not require the calculation of the 3D density profile to identify the boundaries of the droplet. This decreases the computational cost of the contact angle calculation greatly. Moreover, no presumption about the shape of the liquid droplet is needed when using the method introduced in this study. Using this method, the relationship between the size and the contact angle of water nano-droplets on a graphite substrate was studied. It is shown that the contact angle generally decreases by increasing the size of the nano-droplet. The microscopic contact angle of 83.0° was obtained for water on graphite which is in a good agreement with previous experimental and numerical studies. Neglecting other nanoscale effects which may influence the contact angle, the line tension of SPC/E (extended simple point charge model) water was calculated to be 3.6×10 N, which is also in good agreement with the previously calculated values.
本研究介绍了一种计算固液接触角的新方法。该方法利用液滴在固体表面的三维构型，沿接触线计算接触角，并提供角度分布。虽然该方法使用了液滴的三维构型，但不需要计算三维密度分布来确定液滴的边界。这大大降低了接触角计算的计算成本。此外，本研究中介绍的方法不需要对液滴的形状进行假设。使用该方法，研究了水纳米液滴在石墨基底上的尺寸和接触角之间的关系。结果表明，接触角通常随着纳米液滴尺寸的增加而减小。对于水在石墨上的微观接触角 83.0°，与以前的实验和数值研究吻合得很好。忽略可能影响接触角的其他纳米尺度效应，计算出 SPC/E（扩展简单点电荷模型）水的线张力为 3.6×10 N，与之前计算的值也吻合得很好。
