Liu Dandan, Cao Qianqian, Piao Zhongyu, Li Lujuan
College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou, 310014, P.R. China.
College of Information Science and Engineering, Jiaxing University, Jiaxing, 314001, P.R. China.
Chemphyschem. 2022 Dec 16;23(24):e202200184. doi: 10.1002/cphc.202200184. Epub 2022 Sep 12.
The electrowetting effect and related applications of tiny droplets have aroused widespread research interest. In this work, we report molecular dynamics simulations of confinement dynamics of nanodroplets under different droplet-surface interactions and surface distances under an external electric field. So far, the effect of the surface-droplet interactions on electric field-induced dynamics behaviors of droplets in confined spaces has not been extensively studied. Our results show that in the absence of electric field there is a critical value of surface wettability for the shape transition of droplets. Above this value, the droplet is divided into small droplets adhered on the bottom and top surfaces; below this value, the droplets are detached from the surfaces. When an external electric field is applied parallel to the surfaces, the droplet spreads on the surface along the direction of the electric field. It was found that the surface separation significantly influences the transition of the droplet shape. The steady morphology of the droplets under the electric field depends on the surface-droplet interaction and surface separation. We explore the underlying mechanism causing the morphological transition through analyzing the molecular interactions, the number of interracial molecules and the interaction force between the droplets and surfaces. These results provide basic insights into the molecular interactions of nanodroplets under different confined environments, and clues for applications of confined nanodroplets under the control of electric field.
微小液滴的电润湿效应及相关应用引起了广泛的研究兴趣。在这项工作中，我们报道了在外部电场作用下，不同液滴 - 表面相互作用和表面距离条件下纳米液滴受限动力学的分子动力学模拟。到目前为止，表面 - 液滴相互作用对受限空间中液滴电场诱导动力学行为的影响尚未得到广泛研究。我们的结果表明，在没有电场的情况下，液滴形状转变存在一个表面润湿性的临界值。高于此值，液滴分裂成附着在底部和顶部表面的小液滴；低于此值，液滴从表面脱离。当施加平行于表面的外部电场时，液滴沿电场方向在表面上扩散。发现表面间距显著影响液滴形状的转变。电场作用下液滴的稳定形态取决于液滴 - 表面相互作用和表面间距。我们通过分析分子相互作用、界面分子数量以及液滴与表面之间的相互作用力，探索了导致形态转变的潜在机制。这些结果为不同受限环境下纳米液滴的分子相互作用提供了基本见解，并为电场控制下受限纳米液滴的应用提供了线索。
