Petsev Dimiter N
Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131, USA.
J Chem Phys. 2005 Dec 22;123(24):244907. doi: 10.1063/1.2135780.
Electrokinetic phenomena play an important role for the transport in submicrometer-size channels since the electric double layers formed at the walls can occupy a substantial part of the channel volume. This presents a theoretical difficulty and specific problems are usually treated numerically or not comprehensively. In our work we present a theoretical model that allows one to obtain analytical expressions for the transport of fluid (electro-osmotic flow), ions (electric current), and dissolved charged molecules (analytes). The model is based on the weak double layer approximation and has a wide range of validity. An important feature of this theoretical approach is that it is applicable not only to symmetric but also to asymmetric 2:1 and 1:2 electrolytes which exhibit very interesting properties in nanoscale channels. The possibility of affecting the wall electrokinetic zeta potential by applying a transverse voltage bias is analyzed. This transverse bias is used in an attempt to control the transport in the channel and such devices are often called "fluidic field-effect transistors." Our model quantifies the effect of the voltage bias on the zeta potential of the channel wall and therefore can be used for prediction of transport and optimization of separations in such fluidic devices.
电动现象在亚微米尺寸通道中的输运过程中起着重要作用，因为在通道壁上形成的电双层可能占据通道体积的相当一部分。这带来了理论上的困难，具体问题通常通过数值方法处理或未得到全面处理。在我们的工作中，我们提出了一个理论模型，该模型能够得到流体（电渗流）、离子（电流）和溶解的带电分子（分析物）输运的解析表达式。该模型基于弱双层近似，具有广泛的有效性。这种理论方法的一个重要特点是，它不仅适用于对称电解质，也适用于在纳米尺度通道中表现出非常有趣性质的非对称2:1和1:2电解质。分析了通过施加横向电压偏置来影响壁面电动zeta电位的可能性。这种横向偏置被用于尝试控制通道中的输运，此类器件通常被称为“流体场效应晶体管”。我们的模型量化了电压偏置对通道壁zeta电位的影响，因此可用于预测此类流体器件中的输运并优化分离过程。
