An electric field has been extensively used to manipulate fluids and particles via electrokinetic flow in microchannels and nanochannels for various lab-on-a-chip applications. Recent studies have demonstrated the action of a dielectrophoretic-like lift force on near-wall particles in an electrokinetic flow due to the particles’ modifications of the field-line structure adjacent to a planar wall. This work presents a fundamental investigation of the lateral migration of dielectric particles in the electrokinetic flow of buffer solutions of varying molar concentrations through a straight rectangular microchannel. We find that the particle migration-induced electrokinetic centerline focusing is significantly enhanced with the decrease of the buffer concentration. This observed phenomenon may be attributed to the increased surface conduction effect in a lower-concentration buffer that yields a larger Dukhin number, Du. It seems qualitatively consistent with a recent theoretical study that predicts a greater ...

中文翻译：

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电场驱动流体流过直矩形微通道中的表面传导增强类介电泳粒子迁移

电场已被广泛用于通过微通道和纳米通道中的电动流动来操纵流体和粒子，用于各种芯片实验室应用。最近的研究表明，由于粒子对平面壁附近的场线结构进行了修改，因此类似介电泳的升力对电动流动中的近壁粒子的作用。这项工作对电介质颗粒在不同摩尔浓度的缓冲溶液通过直矩形微通道的电动流动中的横向迁移进行了基本研究。我们发现粒子迁移引起的电动中心线聚焦随着缓冲液浓度的降低而显着增强。这种观察到的现象可能是由于在较低浓度的缓冲液中增加了表面传导效应，从而产生了更大的杜欣数，Du。这似乎与最近的一项理论研究在性质上一致，该研究预测了更大的……