Wettability effect on nanoconfined water flow
Wettability effect on nanoconfined water flow
复制标题
润湿性对纳米约束水流的影响
DOI：
10.1073/pnas.1612608114
复制
发表时间：
2017-03-28
影响因子：
11.1
通讯作者：
Dong, Xiaohu
中科院分区：
文献类型：
--
作者：
Wu, Keliu;Chen, Zhangxin;Dong, Xiaohu
被限制在纳米孔中的水的流动与本体水的流动显著不同。此外，了解和控制承压水的流动仍然是一个悬而未决的问题，特别是关于承压水的流动能力是否增加或不相比，散装水。在这里，结合理论分析和分子动力学模拟和文献中的实验数据，我们开发了一个简单的模型，用于限制在纳米孔中的水的流动。我们发现，接触角和纳米孔尺寸可能会大大影响承压水的流动。我们还定量地解释了增加或减少流量的争议。理解和控制水在纳米孔中的流动在理论研究和工业应用中具有巨大的意义。在这里，我们基于有效滑动的概念提出了一个简单的承压水流动模型，有效滑动是真实滑动（取决于接触角）和表观滑动（由承压水粘度的空间变化引起）的线性和，作为函数润湿性以及纳米孔尺寸。该模型的结果表明，承压水的流动能力是通过无滑动哈根-波伊维尔方程计算的具有各种接触角和尺寸的纳米孔的10−1 × 107倍，与文献中53个不同研究案例中的大多数一致。这项工作进一步揭示了从分子动力学模拟和实验的流动能力的增加或减少的争议。
Significance The flow of water confined in nanopores is significantly different from that of bulk water. Moreover, understanding and controlling the flow of the confined water remains an open question, especially concerning whether the flow capacity of the confined water increases or not compared with that of bulk water. Here, combining a theoretical analysis and data from molecular dynamics simulations and experiments in the literature we develop a simple model for the flow of water confined in nanopores. We find that a contact angle and a nanopore dimension may substantially affect the confined water flow. We also quantitatively explain a controversy over an increase or decrease in flow capacity. Understanding and controlling the flow of water confined in nanopores has tremendous implications in theoretical studies and industrial applications. Here, we propose a simple model for the confined water flow based on the concept of effective slip, which is a linear sum of true slip, depending on a contact angle, and apparent slip, caused by a spatial variation of the confined water viscosity as a function of wettability as well as the nanopore dimension. Results from this model show that the flow capacity of confined water is 10−1∼107 times that calculated by the no-slip Hagen–Poiseuille equation for nanopores with various contact angles and dimensions, in agreement with the majority of 53 different study cases from the literature. This work further sheds light on a controversy over an increase or decrease in flow capacity from molecular dynamics simulations and experiments.