Lattice-Boltzmann Simulations of Electrowetting Phenomena.
Lattice-Boltzmann Simulations of Electrowetting Phenomena.
复制标题
DOI：
10.1021/acs.langmuir.9b00098
复制
发表时间：
2018-12
期刊：
影响因子：
--
通讯作者：
É. Ruiz-Gutiérrez;R. Ledesma‐Aguilar
中科院分区：
文献类型：
--
作者：
É. Ruiz-Gutiérrez;R. Ledesma‐Aguilar
当在导电液体和导电（固体）电极之间施加电压差时，观察到液体在固体上扩散。这种现象，通常被称为电润湿，支撑了从液滴微流体到光学的应用中的许多感兴趣的界面现象。在这里，我们提出了一个格子玻尔兹曼方法，可以模拟耦合的流体动力学和静电学运动方程的两相流体作为一种手段来模拟电润湿现象。我们的方法具有建模的晶格玻尔兹曼算法本身内的静电场的优势，消除了对混合方法的需要。我们验证我们的方法，通过再现的静态平衡配置的液滴施加电压，并表明，液滴的表观接触角取决于电压以下的Young-Lippmann方程的接触角为1.50 °。在较高的电压下，我们观察到的接触角的饱和所造成的电和毛细应力之间的竞争，类似于以前的实验观察。我们还研究了被困在导电流体和固体电极之间的电介质膜的稳定性，并发现与基于润滑理论的分析预测很好的一致。最后，我们调查了在很长一段时间内的膜动力学，并报告了类似于先前报道的实验结果的膜破裂和截留的观察。
When a voltage difference is applied between a conducting liquid and a conducting (solid) electrode, the liquid is observed to spread on the solid. This phenomenon, generally referred to as electrowetting, underpins a number of interfacial phenomena of interest in applications that range from droplet microfluidics to optics. Here, we present a lattice-Boltzmann method that can simulate the coupled hydrodynamics and electrostatics equations of motion of a two-phase fluid as a means to model the electrowetting phenomena. Our method has the advantage of modeling the electrostatic fields within the lattice-Boltzmann algorithm itself, eliminating the need for a hybrid method. We validate our method by reproducing the static equilibrium configuration of a droplet subject to an applied voltage and show that the apparent contact angle of the drop depends on the voltage following the Young-Lippmann equation up to contact angles of ≈50°. At higher voltages, we observe a saturation of the contact angle caused by the competition between electric and capillary stresses, similar to previous experimental observations. We also study the stability of a dielectric film trapped between a conducting fluid and a solid electrode and find a good agreement with analytical predictions based on lubrication theory. Finally, we investigate the film dynamics at long times and report observations of film breakup and entrapment similar to previously reported experimental results.