Exploiting the Wall-Induced Non-inertial Lift in Electrokinetic Flow for a Continuous Particle Separation by Size

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• 作者：Xinyu Lu ; Jyh-Ping Hsu ; Xiangchun Xuan
• 刊名：Langmuir
• 出版年：2015
• 出版时间：January 13, 2015
• 年：2015
• 卷：31
• 期：1
• 页码：620-627
• 全文大小：397K
• ISSN：1520-5827

文摘

Separating particles from a heterogeneous mixture is important and necessary in many engineering and biomedical applications. Electrokinetic flow-based continuous particle separation has thus far been realized primarily by the use of particle dielectrophoresis induced in constricted and/or curved microchannels. We develop in this work a new electrokinetic method that exploits the wall-induced non-inertial lift in a straight uniform microchannel to continuously separate particles by intrinsic properties (e.g., size and surface charge). Such an electrically originated lift force arises from the asymmetric electric field distribution around a particle nearby a planar dielectric wall. We demonstrate this method through separating both a binary and ternary mixture of dispersed polystyrene microspheres by size in a T-shaped microchannel. A semi-analytical model is also developed to simulate and understand the particle separation process. The predicted particle trajectories in the entire microchannel agree reasonably well with the experimental measurements.