Non-monotonic dependence of induced-charge electro-osmosis on ion concentration
Non-monotonic dependence of induced-charge electro-osmosis on ion concentration
复制标题
感应电荷电渗对离子浓度的非单调依赖性
DOI：
10.1016/j.colsurfa.2021.126604
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发表时间：
2021-04
期刊：
影响因子：
--
通讯作者：
Teck Neng Wong
中科院分区：
文献类型：
--
作者：
Huicheng Feng;Lingqi Zhao;Xin Zhong;Xingfeng Lei;Teck Neng Wong
感应电荷电渗透是微流体中的一种重要现象，在各种微流控装置中显示出巨大的潜力。然而，iCEO的许多基本机制仍不清楚。离子浓度对iCEO的影响是有争议的。已有文献报道，离子注入速度随离子浓度的增加而单调增大或减小。实验发现，随着氯化钠浓度的增加，离子交换膜的速度先增大后衰减，这涵盖了现有文献中的整个变化范围。随着电场强度的增加，iCeO速度峰值的NaC l浓度也发生变化。此外，研究还发现，随着电场频率的增加，iCeO速度达到最大值，峰值速度的频率取决于微流控芯片的几何形状和基于无体积离子假设的离子浓度。然而，我们发现，由于离子在实际电解液中的空间效应，它随着电场强度的增加而减小。此外，实验还观察到了iCeO涡旋位置的流入-流出不对称性，这与电场和NaC l浓度有关。随着NaC l浓度的增加，旋涡逐渐靠近圆柱体表面，沿轴向的两个旋涡趋于融合。这一新发现可能会丰富iCEO的知识。
Induced-charge electro-osmosis (ICEO) is an important phenomenon in microfluidics as it shows great potential for various microfluidic devices. However, many basic mechanisms of ICEO remain unclear. The effect of ion concentration on ICEO is controversial. Literature has reported that ICEO velocity either monotonically increases or decreases by increasing the ion concentration. In this paper, we experimentally captured that ICEO velocity increases at first and then decays as sodium chloride (NaCl) concentration increases, which covers the whole variation range in the existing literature. The NaCl concentration of peak ICEO velocity varies as the electric field strength increases. In addition, it is known that ICEO velocity achieves a maximum value upon increasing the electric field frequency, and the frequency of peak velocity is determined by the microfluidic chip geometry and the ion concentration based on the volumeless ion assumption. However, we found that it reduces as the electric field strength increases because of the steric effect of ions in real electrolyte solutions. Moreover, an inflow-outflow asymmetry is experimentally observed in ICEO vortex positions, which shows a dependence on the electric field and NaCl concentration. The vortices become close to the cylinder surface and the two vortices along thexaxis tend to merge as NaCl concentration increases. The new findings could enrich the knowledge of ICEO.
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影响因子：
16.6
作者：
Knoska, Juraj;Adriano, Luigi;Heymann, Michael
通讯作者：
Heymann, Michael
DOI：
10.1016/j.colsurfa.2021.126166
发表时间：
2021-01-26
影响因子：
5.2
作者：
Aghaei, Halimeh;Nazar, Ali Reza Solaimany;Varshosaz, Jaleh
通讯作者：
Varshosaz, Jaleh
DOI：
10.1016/j.colsurfa.2018.03.037
发表时间：
2018-06
期刊：
Colloids and Surfaces A: Physicochemical and Engineering Aspects
影响因子：
--
作者：
Partha Sarathi Majee;S. Bhattacharyya
通讯作者：
Partha Sarathi Majee;S. Bhattacharyya
影响因子：
16.6
作者：
Grass, Ingo;Kubitza, Christoph;Wollni, Meike
通讯作者：
Wollni, Meike
影响因子：
2.4
作者：
Boymelgreen, Alicia;Yossifon, Gilad;Miloh, Touvia
通讯作者：
Miloh, Touvia