Nonlinear electrophoresis of dielectric particles in Newtonian fluids
Nonlinear electrophoresis of dielectric particles in Newtonian fluids
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DOI：
10.1002/elps.202200213
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发表时间：
2022-12-28
期刊：
影响因子：
2.9
通讯作者：
Xuan, Xiangchun
中科院分区：
文献类型：
--
作者：
Bentor, Joseph;Dort, Heston;Xuan, Xiangchun
在经典电动学中，介电粒子的电泳速度是所施加电场的线性函数。理论研究预测，由于弯曲粒子上的表面传导不均匀，在高电场下会出现非线性电泳。然而，实验研究已经落后，不足以从根本上理解非线性电泳的参数效应。我们在这项工作中提出了一项系统的实验研究，研究缓冲液浓度、颗粒尺寸和颗粒 Zeta 电位对直矩形微通道中聚苯乙烯颗粒在高达 3 kV/cm 电场中电泳速度的影响。发现测量的非线性电泳粒子速度对所施加的电场表现出 2(+/- 0.5) 阶依赖性，这似乎分别在理论上预测的低电场和高电场的 3 阶和 3/2 阶依赖性内。此外，所获得的非线性电泳颗粒迁移率随着缓冲液浓度（对于相同颗粒）和颗粒尺寸（对于具有相似zeta电位的颗粒）的降低或颗粒zeta电位（对于具有相似尺寸的颗粒）的增加而增加。这些观察结果都与高电场的理论预测一致。
In classical electrokinetics, the electrophoretic velocity of a dielectric particle is a linear function of the applied electric field. Theoretical studies have predicted the onset of nonlinear electrophoresis at high electric fields because of the nonuniform surface conduction over the curved particle. However, experimental studies have been left behind and are insufficient for a fundamental understanding of the parametric effects on nonlinear electrophoresis. We present in this work a systematic experimental study of the effects of buffer concentration, particle size, and particle zeta potential on the electrophoretic velocity of polystyrene particles in a straight rectangular microchannel for electric fields of up to 3 kV/cm. The measured nonlinear electrophoretic particle velocity is found to exhibit a 2(+/- 0.5)-order dependence on the applied electric field, which appears to be within the theoretically predicted 3- and 3/2-order dependences for low and high electric fields, respectively. Moreover, the obtained nonlinear electrophoretic particle mobility increases with decreasing buffer concentration (for the same particle) and particle size (for particles with similar zeta potentials) or increasing particle zeta potential (for particles with similar sizes). These observations are all consistent with the theoretical predictions for high electric fields.