Electrophoresis and electric conduction in a salt‐free suspension of charged particles

Luo, Ren H.; Keh, Huan J.

doi:10.1002/elps.202100181

Cited by 3 publications

(2 citation statements)

References 36 publications

(74 reference statements)

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“…A system is under the influence of a uniform EF if the field strength is constant in the entire system [39]. The migration of particles under the effects of an EF is called EP [40], which requires particles to have an inherent electrical charge [41]. A basic EP‐based system is formed by two electrodes of opposite charge, an anode (negative charge) and a cathode (positive charge), bridged by the presence of a conducting medium called an electrolyte solution.…”

Section: Theorymentioning

confidence: 99%

Electropatterning—Contemporary developments for selective particle arrangements employing electrokinetics

et al. 2023

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The selective positioning and arrangement of distinct types of multiscale particles can be used in numerous applications in microfluidics, including integrated circuits, sensors and biochips. Electrokinetic (EK) techniques offer an extensive range of options for label‐free manipulation and patterning of colloidal particles by exploiting the intrinsic electrical properties of the target of interest. EK‐based techniques have been widely implemented in many recent studies, and various methodologies and microfluidic device designs have been developed to achieve patterning two‐ and three‐dimensional (3D) patterned structures. This review provides an overview of the progress in electropatterning research during the last 5 years in the microfluidics arena. This article discusses the advances in the electropatterning of colloids, droplets, synthetic particles, cells, and gels. Each subsection analyzes the manipulation of the particles of interest via EK techniques such as electrophoresis and dielectrophoresis. The conclusions summarize recent advances and provide an outlook on the future of electropatterning in various fields of application, especially those with 3D arrangements as their end goal.

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Section: Theorymentioning

confidence: 99%

Electropatterning—Contemporary developments for selective particle arrangements employing electrokinetics

et al. 2023

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“…Chiang et al [24] and He et al [25] also numerically predicted the electrophoretic mobility of concentrated salt-free suspensions of charged hard and porous spheres, respectively, using the cell model. Recently, the electrophoresis and electric conduction of salt-free suspensions of hard spherical particles have been analyzed by Luo and Keh [26] using the cell model to investigate the effects of particle concentration. However, the particle concentration effects on the electrophoretic mobility and electric conductivity in a salt-free suspension of charged soft particles [27,28] of arbitrary volume fraction have not been analytically studied.…”

Section: Introductionmentioning

confidence: 99%

Electrophoretic Mobility and Electric Conductivity of Salt-Free Suspensions of Charged Soft Particles

Lin

Keh

2021

Colloids and Interfaces

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A unit cell model is employed to analyze the electrophoresis and electric conduction in a concentrated suspension of spherical charged soft particles (each is a hard core coated with a porous polyelectrolyte layer) in a salt-free medium. The linearized Poisson–Boltzmann equation applicable to a unit cell is solved for the equilibrium electrostatic potential distribution in the liquid solution containing the counterions only surrounding a soft particle. The counterionic continuity equation and modified Stokes/Brinkman equations are solved for the ionic electrochemical potential energy and fluid velocity distributions, respectively. Closed-form formulas for the electrophoretic mobility of the soft particles and effective electric conductivity of the suspension are derived, and the effect of particle interactions on these transport characteristics is interesting and significant. Same as the case in a suspension containing added electrolytes under the Debye–Hückel approximation, the scaled electrophoretic mobility in a salt-free suspension is an increasing function of the fixed charge density of the soft particles and decreases with increases in the core-to-particle radius ratio, ratio of the particle radius to the permeation length in the porous layer, and particle volume fraction, keeping the other parameters unchanged. The normalized effective electric conductivity of the salt-free suspension also increases with an increase in the fixed charge density and with a decrease in the core-to-particle radius ratio, but is not a monotonic function of the particle volume fraction.

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Transient electrophoresis of colloidal particles in a salt-free medium

Ohshima

2024

Front. Lab. Chip. Technol.

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A general theory is developed for the time dependent transient electrophoretic mobility of spherical colloidal particles in a salt-free liquid medium containing only counterions when a step external electric field is suddenly applied to the colloidal suspension. It is found that as in the case of the steady electrophoretic mobility in a salt-free medium, there is a certain critical value of the particle surface charge separating two cases, that is, the low-surface-charge case and the high-surface-charge case. In the latter case the counterion condensation takes place near the particle surface. For the low-surface charge case, the transient electrophoretic mobility agrees with that of a sphere in an electrolyte solution in the limit of very low electrolyte concentrations. For the high-surface-charge case, however, the transient mobility becomes independent of the particle surface charge because of the counterion condensation effects. A simple expression is derived for the ratio of the transient electrophoretic mobility to the steady electrophoretic mobility, which is found to take the same form irrespective of the magnitude of the particle surface charge. Using this equation, it is now possible to predict how the system will approach its final steady state.

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Electrophoresis and electric conduction in a salt‐free suspension of charged particles

Cited by 3 publications

References 36 publications

Electropatterning—Contemporary developments for selective particle arrangements employing electrokinetics

Electropatterning—Contemporary developments for selective particle arrangements employing electrokinetics

Electrophoretic Mobility and Electric Conductivity of Salt-Free Suspensions of Charged Soft Particles

Transient electrophoresis of colloidal particles in a salt-free medium

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