Influence of polyelectrolyte shape on its sedimentation behavior: effect of relaxation electric field

Yeh, P.; Hsu, Jyh‐Ping; Tseng, Shiojenn

doi:10.1039/c4sm01351d

Cited by 5 publications

(4 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We consider the range of

C

below

5 \times 10^{6}

so that

{Re}_{f} \leq 0.9

. As pointed out by several authors ([16, 36] and the references therein), for tube centrifuges or ultracentrifuges, the

g

‐factor can create

C

up to

10^{6}

. Results show that the dimensional sedimentation velocity increases linearly with

{Re}_{f}

and the velocity at a fixed

{Re}_{f}

enhances as the slip length is increased.…”

Section: Resultsmentioning

confidence: 94%

Settling of a charged hydrophobic rigid colloid in aqueous media under generalized gravitational field

et al. 2020

View full text Add to dashboard Cite

The hindrance created by the induced electric filed on the sedimentation of a charged colloid in an aqueous media is studied through numerical modeling. The colloid is considered to be hydrophobic, sedimenting under gravity or a centrifugal force (generalized gravity). The deformation of the charge cloud around the colloid induces an electric field, which generates electrical dipole force on the colloid. The sedimentation velocity is governed by the balance of an electric force, hydrodynamic drag, and gravitational force. Governing equations based on the first principle of electrokinetics is solved numerically through a control volume approach. The dependence of the sedimentation velocity on the electrical properties and slip length of the colloid is investigated. The sedimentation velocity of the charged colloid is slower than the corresponding uncharged particle and this deviation magnifies as the charge density as well as particle slip length is increased. An enhanced g‐factor creates a size dependency of the charged colloids. The induced sedimentation field is obtained to analyze the electrokinetics. Surface hydrophobicity enhances the sedimentation velocity, which in turn manifests the induced sedimentation field. However, the sedimentation velocity of a charged hydrophobic colloid is lower than the corresponding uncharged hydrophobic particle and this deviation manifests as slip length is increased.

show abstract

“…We consider the range of

C

below

5 \times 10^{6}

so that

{Re}_{f} \leq 0.9

. As pointed out by several authors ([16, 36] and the references therein), for tube centrifuges or ultracentrifuges, the

g

‐factor can create

C

up to

10^{6}

. Results show that the dimensional sedimentation velocity increases linearly with

{Re}_{f}

and the velocity at a fixed

{Re}_{f}

enhances as the slip length is increased.…”

Section: Resultsmentioning

confidence: 94%

Settling of a charged hydrophobic rigid colloid in aqueous media under generalized gravitational field

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The external force is given as f ̃ ̲ = C g ̲ , where double-struckC ( C ≥ 0 ) is a multiplicative factor or g -factor, which controls the strength of the centrifugal force, and g̲ is the gravity vector. Large values of double-struckC (equal to 10 6 ) correspond to modern centrifugal devices. , Throughout the remainder of the paper, a tilde ( ∼ ) denotes a dimensional parameter, while the absence of one denotes the dimensionless counterpart of this parameter. The human blood plasma behaves as an incompressible, electrolytic, viscoelastic solution with constant density, ρ ̃ f , relaxation time, λ ̃ , and total, zero shear rate viscosity, η ̃ t .…”

Section: Problem Formulationmentioning

confidence: 99%

“…The external force is given as , where is a multiplicative factor or g -factor, which controls the strength of the centrifugal force, and g̲ is the gravity vector. Large values of (equal to 10 6 ) correspond to modern centrifugal devices. , Throughout the remainder of the paper, a tilde ( ∼ ) denotes a dimensional parameter, while the absence of one denotes the dimensionless counterpart of this parameter. The human blood plasma behaves as an incompressible, electrolytic, viscoelastic solution with constant density, ρ ̃ f , relaxation time, λ ̃ , and total, zero shear rate viscosity, η ̃ t .…”

Section: Problem Formulationmentioning

confidence: 99%

Sedimentation of a Charged Spherical Particle in a Viscoelastic Electrolyte Solution

Kouni,

Moschopoulos,

Dimakopoulos

et al. 2023

Langmuir

View full text Add to dashboard Cite

When a charged particle translates through an electrolyte solution, the electric double layer around it deforms in response to the fluid motion and creates an electric force opposite the direction of motion, decreasing the settling velocity. This is a multidisciplinary phenomenon that combines fluid mechanics and electrodynamics, differentiating it from the classical problem of an uncharged sedimenting particle. It has many applications varying from mechanical to biomedical, such as in drug delivery in blood through charged microparticles. Related studies so far have focused on Newtonian fluids, but recent studies have proven that many biofluids, such as human blood plasma, have elastic properties. To this end, we perform a computational study of the steady sedimentation of a spherical, charged particle in human blood plasma due to the centrifugal force. We used the Giesekus model to describe the rheological behavior of human blood plasma. Assuming axial symmetry, the governing equations include the momentum and mass balances, Poisson’s equation for the electric field, and the species conservation. The finite size of the ions is considered through the local-density approximation approach of Carnahan–Starling. We perform a detailed parametric analysis, varying parameters such as the ζ potential, the size of the ions, and the centrifugal force exerted upon the particle. We observe that as the ζ potential increases, the settling velocity decreases due to a stronger electric force that slows the particle. We also conduct a parametric analysis of the relaxation time of the material to investigate what happens generally in viscoelastic electrolyte solutions and not only in human blood plasma. We conclude that elasticity plays a crucial role and should not be excluded from the study. Finally, we examine under which conditions the assumption of point-like ions gives different predictions from the Carnahan–Starling approach.

show abstract

“…Based on a perturbation approach, Keh and Ding derived the dependence of the sedimentation velocity of a rigid sphere having a constant surface charge density in an aqueous, Newtonian salt solution on the thickness of double layer. Taking account of the effect of double-layer relaxation, Yeh et al modeled the settling of a deformable polyelectrolyte in an unbounded salt solution subject to an applied centrifugal field. The sedimentation behavior of the polyelectrolyte was explained by its effective charge density and the local electric field induced near it.…”

Section: Introductionmentioning

confidence: 99%

Sedimentation of a pH-Regulated Nanoparticle in a Generalized Gravitational Field

2017

Self Cite

View full text Add to dashboard Cite

Taking account of the effect of double-layer polarization, we modeled the sedimentation of a pH-regulated nanoparticle in a generalized field. The influences of the radius and the density of the functional groups of the particle, the pH, and the bulk salt concentration of the liquid phase and the Reynolds number Re on the sedimentation behavior of the particle are examined in detail. We found that as Re increases, because more counterions are dragged away from the particle surface, its averaged charge density decreases accordingly. The smaller the particle, the thicker the double layer so that double-layer polarization is more significant and the distribution of the surface charge density is more nonuniform. Interestingly, the smaller the particle, the higher the averaged surface charge density, but the smaller the electric force acting on it. If the particle is sufficiently large (300 nm in radius), its averaged surface charge density is insensitive to Re as it varies from 0.0025 to 0.04 but can have an appreciable difference (ca. 10%) if it is small (75 nm).

show abstract

Influence of polyelectrolyte shape on its sedimentation behavior: effect of relaxation electric field

Cited by 5 publications

References 25 publications

Settling of a charged hydrophobic rigid colloid in aqueous media under generalized gravitational field

Settling of a charged hydrophobic rigid colloid in aqueous media under generalized gravitational field

Sedimentation of a Charged Spherical Particle in a Viscoelastic Electrolyte Solution

Sedimentation of a pH-Regulated Nanoparticle in a Generalized Gravitational Field

Contact Info

Product

Resources

About