Ionic selectivity of single nanochannels
Ionic selectivity of single nanochannels
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DOI：
10.1021/nl800949k
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发表时间：
2008-07-01
期刊：
影响因子：
10.8
通讯作者：
Siwy, Zuzanna
中科院分区：
文献类型：
--
作者：
Vlassiouk, Ivan;Smirnov, Sergei;Siwy, Zuzanna
人们对单纳米通道离子装置越来越感兴趣，例如控制传输离子类型的离子过滤器和整流离子流的离子二极管。在本文中，我们从理论上研究了尺寸、表面电荷、电解质浓度和施加偏压对纳米孔性能的重要性。我们将泊松、能斯特-普朗克 (PNP) 和纳维-斯托克斯 (NS) 方程的数值解与其一维解析近似进行比较。我们表明，通过减少纳米孔的长度，离子电流和离子选择性会受到纳米通道外部过程的影响。电渗的贡献是显而易见的，特别是对于高电荷纳米通道，但其影响微不足道，这证明在许多情况下使用简单的一维近似是合理的。提供了纳米孔选择性降低且离子电流开始饱和的临界电场的估计。
There has been an increasing interest in single nanochannel ionic devices, such as ionic filters that control the type of transported ions and ionic diodes that rectify the ionic flow. In this article, we theoretically investigate the importance of the dimensions, surface charge, electrolyte concentration, and applied bias on nanopore performance. We compare numerical solutions of the Poisson, Nernst-Planck (PNP), and Navier-Stokes (NS) equations with their one-dimensional, analytical approximations. We show that by decreasing the length of the nanopore, the ionic current and ionic selectivity become affected by processes outside the nanochannel. The contribution of electroosmosis is noticeable, especially for highly charged nanochannels, but is insignificant, justifying the use of the simple one-dimensional approximation in many cases. Estimates for the critical electric field at which the nanopore selectivity decreases and the ion current starts to saturate are provided.