Electrohydrodynamic Flow through a 1 mm2 Cross-Section Pore Placed in an Ion-Exchange Membrane
Electrohydrodynamic Flow through a 1 mm2 Cross-Section Pore Placed in an Ion-Exchange Membrane
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DOI：
10.1021/jp5071538
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发表时间：
2015-01-08
影响因子：
3.3
通讯作者：
Kawano, Satoyuki
中科院分区：
文献类型：
--
作者：
Doi, Kentaro;Yano, Ayako;Kawano, Satoyuki
近年来，离子电流的控制已经被认为是与水溶液中的单分子和微粒的有效运输相关的最重要的问题之一。然而，复杂的液体流动，通常是由施加电势引起的，这使得它很难解决在这一领域的一些未解决的问题。特别是，发生在电非中性领域的非平衡现象必须得到更彻底的理解。在这里，我们报告的发展的理论模型的液体流动离子相互作用，而专注于所谓的电流体动力学（EHD）流。我们还讨论了一个实验系统的发展，光学和电学观察EHD流量使用1毫米（2）横截面孔放置在离子交换膜的阳离子和阴离子流可以分离，而不使用带电的环境。虽然微/纳米尺寸的流动通道通常被应用于诱导双电层重叠以利用强电渗效应，但我们的系统不需要这种费力的制造过程。相反，我们可视化EHD流使用毫米大小的孔浸泡在碱性水溶液中。在该装置中，通过施加几伏的电势，可以清楚地观察到沿着离子流的方向沿着通过孔的液体流，其速度达到1 mm/s的数量级。此外，从理论上阐明了与离子响应相关的瞬态现象。
In recent years, the control of ionic currents has come to be recognized as one of the most important issues related to the efficient transport of single molecules and microparticles in aqueous solutions. However, the complicated liquid flows that are usually induced by applying electric potentials have made it difficult to address a number of unsolved problems in this area. In particular, the nonequilibrium phenomena that occur in electrically non-neutral fields must be more thoroughly understood. Herein, we report on the development of a theoretical model of liquid flows resulting from ion interactions while focusing on the so-called electrohydrodynamic (EHD) flow. We also discuss the development of an experimental system to optically and electrically observe EHD flows using a 1 mm(2) cross-section pore placed in an ion-exchange membrane where cation and anion flows can be separated without the use of a charged environment. Although micro/nanosized flow channels are usually applied to induce electric double layer overlaps to utilize strong electroosmotic effects, our system does not require such laborious fabrication processes. Instead, we visualize EHD flows by using a millimeter size pore immersed in an alkaline aqueous solution. In this setup, liquid flows passing through the pore along the direction of ion flow, whose velocity reaches on the order of 1 mm/s, can be clearly observed by applying a few volts of electric potential. Furthermore, the transient phenomena associated with ionic responses are theoretically elucidated.