Electrophoresis of a weakly charged dielectric droplet with constant surface charge density in a chargeless cylindrical pore is investigated theoretically in this study, focusing on the boundary confinement effect of the double layer, which in turn determines the ultimate motion of the droplet. A patched pseudo‐spectral method based on the Chebyshev polynomial is adopted to solve the resulting governing fundamental electrokinetic equations. Mobility reversal, among other interesting phenomena, is observed when the droplet is in a narrow cylindrical pore. No such observation was made in the corresponding motion of a rigid particle. The droplet with a thick double layer may even move against the prediction based on the Coulomb electrostatic law, for instance, a positively charged droplet may move against the electric field. The significant enhancement of the motion‐deterring double layer polarization due to the severe steric boundary confinement within a narrow cylindrical pore is found to be responsible for this seemingly peculiar phenomenon. Moreover, smaller droplets may move in the opposite direction of the larger ones. The results are useful in capillary electrophoresis involving droplets in particular and migration of droplets through narrow channels in general.

中文翻译：

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圆柱形孔中弱带电介电流体液滴的电泳

本研究从理论上研究了表面电荷密度恒定的弱带电介电液滴在无电荷圆柱形孔中的电泳，重点研究了双层的边界限制效应，这反过来又决定了液滴的最终运动。采用基于切比雪夫多项式的修补伪谱方法来求解所得的控制基本动电方程。当液滴处于狭窄的圆柱形孔中时，可以观察到流动性反转以及其他有趣的现象。在刚性粒子的相应运动中没有进行这样的观察。具有厚双层的液滴甚至可能与基于库仑静电定律的预测相反地移动，例如，带正电的液滴可能会与电场相反地移动。人们发现，由于狭窄的圆柱形孔隙内严格的空间边界限制，运动阻止双层极化的显着增强是造成这种看似奇特现象的原因。此外，较小的液滴可能沿与较大的液滴相反的方向移动。该结果对于特别涉及液滴的毛细管电泳以及通常液滴通过狭窄通道的迁移是有用的。