Ye Chunzhen, Li Dongqing
Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, M5S 3G8, Canada.
J Colloid Interface Sci. 2002 Jul 15;251(2):331-8. doi: 10.1006/jcis.2002.8438.
This paper considered electrophoretic motion of a sphere in an aqueous electrolyte solution in a microchannel under the gravitational field. In an externally applied electric field, the negatively charged sphere will move toward the anode. At the same time, the sphere will move toward the lower channel wall due to the density difference and the gravity. When the sphere moves very close to the lower wall, the buoyancy, the electric double layer interaction force, and the van der Waals force balance the gravity force, so the sphere moves parallel to the lower wall. A theoretical model for the electrophoretic motion of a sphere in a microchannel, with the consideration of the electrophoretic retardation effect, is presented in this paper. It was found that the sphere's motion in the microchannel is affected by its size, the density difference, the zeta potentials of the sphere and the channel wall, and the applied electric strength. The effects of these factors on the sphere's transport distance in the microchannel are discussed. It was found that the spheres with the same surface charge could be separated by their size within a certain range of ka in aqueous solutions in the microchannel.
本文研究了在重力场下微通道中球形颗粒在水性电解质溶液中的电泳运动。在外部施加的电场中，带负电荷的球形颗粒会向阳极移动。同时，由于密度差异和重力作用，球形颗粒会向下通道壁移动。当球形颗粒非常靠近下壁时，浮力、电双层相互作用力和范德华力与重力相平衡，因此球形颗粒会平行于下壁移动。本文提出了一个考虑电泳延迟效应的微通道中球形颗粒电泳运动的理论模型。研究发现，微通道中球形颗粒的运动受其尺寸、密度差异、球形颗粒与通道壁的zeta电位以及外加电场强度的影响。讨论了这些因素对微通道中球形颗粒传输距离的影响。研究发现，在微通道的水溶液中，具有相同表面电荷的球形颗粒在一定的ka范围内可以按尺寸分离。
