Geng Xinran, Yu Miao, Zhang Wei, Liu Qiwei, Yu Xiaopeng, Lu Yang
Jilin Provincial Key Laboratory for Numerical Simulation, Jilin Normal University, Siping, Jilin, 136000, P. R. China.
School of Materials Science and Engineering, Institute for Advanced Materials, Jiangsu University, Zhenjiang, 212013, P. R. China.
Sci Rep. 2019 Dec 12;9(1):18957. doi: 10.1038/s41598-019-55491-2.
In this work, the slip behavior and structure of liquid water flowing between two charged solid planar walls were investigated using non-equilibrium molecular dynamics simulations. The upper and lower walls are positive and negative charged, respectively. It was shown that the slip length increases at smaller water-solid interaction energy and become smaller with increasing the surface charge density. At the largest surface charge density, the slip length nearly independent of the water-solid interaction energy. The relationship between the slip length and surface charge density and water-solid interaction energy was rationalized by considering the static structure factor of liquid water. Interestingly, the positive charged surface induces less ordering structure and larger slip at the small surface charge density than that by the negative charged surface. While, at large surface charge density, the opposite correlation is observed. Furthermore, we find that the relationship between the slip length and the normalized main peak of static structure factor collapses onto a single curve for different water-solid interaction energies and surface charge densities. The results of the present work open perspectives for modeling complex systems with combined effects of surface charge and wettability.
在这项工作中，我们使用非平衡分子动力学模拟研究了在两个带电固体平面壁之间流动的液态水的滑移行为和结构。上壁和下壁分别带正电和负电。结果表明，滑移长度在较小的水-固相互作用能时增加，而随着表面电荷密度的增加而减小。在最大表面电荷密度下，滑移长度几乎与水-固相互作用能无关。通过考虑液态水的静态结构因子，合理化了滑移长度与表面电荷密度以及水-固相互作用能之间的关系。有趣的是，在小表面电荷密度下，带正电的表面比带负电的表面诱导出的有序结构更少，滑移更大。而在大表面电荷密度下，则观察到相反的相关性。此外，我们发现，对于不同的水-固相互作用能和表面电荷密度，滑移长度与静态结构因子归一化主峰之间的关系坍缩到一条单一曲线上。本工作的结果为模拟具有表面电荷和润湿性综合效应的复杂系统开辟了前景。
