Diffusiophoresis of a charged particle in a charged cavity with arbitrary electric double layer thickness

Chiu, Ya C.; Keh, Huan J.

doi:10.1007/s10404-018-2102-0

Cited by 7 publications

(4 citation statements)

References 37 publications

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“…For very thin electric double layers (κ a → ∞), eqs and become where and ξ = a / b . For very thick double layers (κ b → 0), eqs and become As a / b = 0 (the cavity wall is very far from the porous sphere), eqs and reduce to As a / b = 1 (the particle fills the cavity up entirely), eqs and lead to Interestingly, U 01 /β U * in this limit can be finite, in contrast to zero for a confined charged hard sphere. , This singular outcome is understood knowing that the ionic fluid in the permeable and slip porous particle is still driven to flow by the induced electric field shown in eq as long as λ a is finite, and thus the particle must migrate according to its force balance.…”

Section: Resultsmentioning

confidence: 99%

“…Interestingly, U 01 /βU* in this limit can be finite, in contrast to zero for a confined charged hard sphere. 30,32 This singular outcome is understood knowing that the ionic fluid in the permeable and slip porous particle is still driven to flow by the induced electric field shown in eq 8b as long as λa is finite, and thus the particle must migrate according to its force balance. The dimensionless velocities U 01 /βU* and U 10 /βU* as calculated from eqs 21a and 21b are plotted versus the parameters κa, λa, and a/b in Figures 2 and 3, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…The system of a colloidal sphere moving in a spherical cavity can be an idealized model for the diffusiophoresis in microfluidic devices or dead-end pores of self-regulated drug delivery systems. , Actually, the diffusiophoretic motions of a hard spherical particle with a thin polarized double layer and an arbitrary value of κ a in a concentric charged spherical cavity have been analytically examined. Also, the diffusiophoresis of a soft sphere within a nonconcentric uncharged spherical cavity has been numerically examined .…”

Section: Introductionmentioning

confidence: 99%

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Diffusiophoresis of a Charged Porous Particle in a Charged Cavity

Chiu

Keh

2018

J. Phys. Chem. B

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The quasi-steady diffusiophoresis of a charged porous sphere situated at the center of a charged spherical cavity filled with a liquid solution of a symmetric electrolyte is analyzed. The porous particle can represent a solvent-permeable and ion-penetrable polyelectrolyte molecule or floc of nanoparticles in which fixed charges and frictional segments are uniformly distributed, whereas the spherical cavity can denote a charged pore involved in microfluidic or drug-delivery systems. The linearized electrokinetic differential equations governing the ionic concentration, electric potential, and fluid velocity distributions in the system are solved by using a perturbation method with the fixed charge density of the particle and the ζ-potential of the cavity wall as the small perturbation parameters. An expression for the diffusiophoretic (electrophoretic and chemiphoretic) mobility of the confined particle with arbitrary values of a/b, κa, and λa is obtained in closed form, where a and b are the radii of the particle and cavity, respectively; κ and λ are the reciprocals of the Debye screening length and the length characterizing the extent of flow penetration into the porous particle, respectively. The presence of the charged cavity wall significantly affects the diffusiophoretic motion of the particle in typical cases. The diffusio-osmotic (electro-osmotic and chemiosmotic) flow occurring at the cavity wall can substantially alter the particle velocity and even reverse the direction of diffusiophoresis. In general, the particle velocity decreases with an increase in a/b, increases with an increase in κa, and decreases with an increase in λa, but exceptions exist.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Diffusiophoresis of a Charged Porous Particle in a Charged Cavity

Chiu

Keh

2018

J. Phys. Chem. B

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“…The diffusiophoresis of a charged sphere in a charged spherical cavity can be used to model diffusiophoretic motions in lab-on-a-chip devices and dead-end pores involving self-regulated drug delivery [33,34]. In fact, the diffusiophoresis of a charged hard or porous sphere with a thin polarized or an arbitrary double layer situated at the center of a charged spherical cavity [35,36] and the diffusiophoresis of a charged soft sphere with an arbitrary double layer inside a nonconcentric uncharged spherical cavity [37] have been studied theoretically. However, the effect of a charged boundary on the diffusiophoretic motion of a soft particle has not been investigated.…”

Section: Introductionmentioning

confidence: 99%

Diffusiophoresis of a Charged Soft Sphere in a Charged Spherical Cavity

Chen,

Keh

2024

Colloids and Interfaces

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The quasi-steady diffusiophoresis of a soft particle composed of an uncharged hard sphere core and a uniformly charged porous surface layer in a concentric charged spherical cavity full of a symmetric electrolyte solution with a concentration gradient is analyzed. By using a regular perturbation method with small fixed charge densities of the soft particle and cavity wall, the linearized electrokinetic equations relevant to the fluid velocity field, electric potential profile, and ionic concentration distributions are solved. A closed-form formula for the diffusiophoretic (electrophoretic and chemiphoretic) velocity of the soft particle is obtained as a function of the ratios of the core-to-particle radii, particle-to-cavity radii, particle radius to the Debye screening length, and particle radius to the permeation length in the porous layer. In typical cases, the confining charged cavity wall significantly influences the diffusiophoresis of the soft particle. The fluid flow caused by the diffusioosmosis (electroosmosis and chemiosmosis) along the cavity wall can considerably change the diffusiophoretic velocity of the particle and even reverse its direction. In general, the diffusiophoretic velocity decreases with increasing core-to-particle radius ratios, particle-to-cavity radius ratios, and the ratio of the particle radius to the permeation length in the porous layer, but increases with increasing ratios of the particle radius to the Debye length.

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Diffusiophoretic velocity of a large spherical colloidal particle in a solution of general electrolytes

Ohshima

2021

Colloid Polym Sci

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Diffusiophoresis of a charged particle in a charged cavity with arbitrary electric double layer thickness

Cited by 7 publications

References 37 publications

Diffusiophoresis of a Charged Porous Particle in a Charged Cavity

Diffusiophoresis of a Charged Porous Particle in a Charged Cavity

Diffusiophoresis of a Charged Soft Sphere in a Charged Spherical Cavity

Diffusiophoretic velocity of a large spherical colloidal particle in a solution of general electrolytes

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