Diffusiophoresis of Concentrated Suspensions of Liquid Drops

Lou, James; Lee, Eric

doi:10.1021/jp8008749

Cited by 29 publications

(32 citation statements)

References 36 publications

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“…thick EDL and small gap between the particle surface and nanopore wall), the EDL surrounding the charged nanoparticle is compressed by the nanopore wall, and the type I DLP mainly arises from the EDL compression by the boundary. [34,37,38,48] If the EDL compression by the nanopore wall is insignificant, as the ratio a/a p increases, the degree of DLP decreases, leading to the decrease in the induced electrophoresis arising from the DLP-induced electric fields.…”

Section: Effect Of the Particle Surface Charge Density S Pmentioning

confidence: 99%

Diffusiophoresis of an Elongated Cylindrical Nanoparticle along the Axis of a Nanopore

et al. 2010

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The translation of a charged, elongated cylindrical nanoparticle along the axis of a nanopore driven by an imposed axial salt concentration gradient is investigated using a continuum theory, which consists of the ionic mass conservation equations for the ionic concentrations, the Poisson equation for the electric potential in the solution, and the modified Stokes equations for the hydrodynamic field. The diffusiophoretic motion is driven by the induced electrophoresis and chemiphoresis. The former is driven by the generated overall electric field arising from the difference in the ionic diffusivities and the double layer polarization, while the latter is generated by the induced osmotic pressure gradient around the charged particle. The induced diffusiophoretic motion is investigated as functions of the imposed salt concentration gradient, the ratio of the particle's radius to the double layer thickness, the cylinder's aspect ratio (length/radius), the ratio of the nanopore size to the particle size, the surface charge densities of the nanoparticle and the nanopore, and the type of the salt used. The induced diffusiophoretic motion of a nanorod in an uncharged nanopore is mainly governed by the induced electrophoresis, driven by the induced electric field arising from the double layer polarization. The induced particle motion is driven by the induced electroosmotic flow, if the charges of the nanorod and nanopore wall have the same sign.

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Section: Effect Of the Particle Surface Charge Density S Pmentioning

confidence: 99%

Diffusiophoresis of an Elongated Cylindrical Nanoparticle along the Axis of a Nanopore

et al. 2010

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“…The details can also be found elsewhere. 19,21,22,24,25 ■ RESULTS AND DISCUSSION We first make sure the numerical convergence by checking the grid independence of the calculation results in terms of the solutions do not change anymore with further refinement of the computation domain. It turns out that 120 grid points in the outer porous layer and the suspending medium each are sufficient.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Academic studies of the diffusiophoresis phenomenon can be found on both experimental and theoretical fronts in the literature. ,,, Theoretical studies on diffusiophoresis for rigid particles have been conducted extensively, ranging from a single isolated particle to suspensions, lowly charged to highly charged particle surfaces, finite or thin double layers, with or without a nearby or confining boundary, and so on. ,,,,− Nonrigid particles like liquid drops and porous particles were investigated as well. − Porous particles in particular, which are permeable to the surrounding electrolyte solution, can be used to model polyelectrolytes like proteins and DNA under certain circumstances, for instance. ,, Their diffusiophoretic behavior have been examined thoroughly in electrolyte solution with or without diffusion potential. On the other hand, there are particles of partial porous nature as well, such as a composite particle with a spherical inner rigid core covered by a concentric outer porous layer of finite thickness. , The outer porous layer can be a natural membrane or an artificial polymer layer, which sometimes is called the “fussy layer” or the “polyelectrolyte layer” .…”

Section: Introductionmentioning

confidence: 99%

Diffusiophoresis of a Highly Charged Soft Particle in Electrolyte Solutions

Lee

Chang

et al. 2021

Langmuir

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Diffusiophoresis of a soft particle suspended in an infinite medium of symmetric binary electrolyte solution is investigated theoretically in this study, focusing on the chemiphoresis component when there is no global diffusion potential in the bulk solution. The general governing electrokinetic equations are solved with a pseudo-spectral method based on Chebyshev polynomials, and particle mobility, defined as the particle velocity per unit concentration gradient, is calculated. Parameters of electrokinetic interest are examined, in general, to explore their respective impact upon particle motion, such as the fixed charge density and permeability in the outer porous layer, the surface charge density and size of the inner rigid core, and the electrolyte strength in the solution. Nonlinear phenomena such as the motion-deterring double-layer polarization and the counterion condensation effects are scrutinized, in particular, for highly charged soft particles. Mobility reversal is observed in some range of electrolyte strength for highly charged particles. The generation of an axisymmetric counterclockwise vortex flow across the porous layer is found to be responsible for it. The onset of the mobility reversal is synchronized with the appearance or disappearance of this vortex flow. Mobility reversal may happen more than once, with particle moving toward or away from the region of higher solute concentration. The latter is undesirable in the application of drug delivery and thus should be avoided by delicate control of the electrokinetic environment. A local micro diffusion potential is discovered, which always speeds up the migration of coions and slows down that of counterions to guarantee that there is no net electric current across the double layer. Moreover, multilayer structure of the double-layer polarization is discovered when the electrolyte strength is high. The study presented here provides insight and crucial information for practical applications of soft particles, such as drug delivery.

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“…The spontaneous movement of charged colloids in an electrolyte solution subject to an applied salt gradient, known as diffusiophoresis [1], has been studied recently by many investigators both theoretically [2][3][4][5][6][7][8][9][10][11][12][13] and experimentally [14][15][16][17][18]. Compared to conventional electrophoresis operations, diffusiophoresis has the advantages such as no Joules heat effect [19] and metals in electrical contact [20].…”

Section: Introductionmentioning

confidence: 99%

Diffusiophoresis of a polyelectrolyte in a salt concentration gradient

Liu

Hsu

et al. 2012

Electrophoresis

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The diffusiophoresis of a polyelectrolyte subject to an applied salt concentration gradient is modeled theoretically. The entirely porous type of particle is capable of simulating entities such as DNA, protein, and synthetic polymeric particles. The dependence of the diffusiophoretic behavior of the polyelectrolyte on its physical properties, and the types of ionic species and their bulk concentrations are discussed in detail. We show that in addition to the effects coming from the polarization of double layer and the difference in the ionic diffusivities, the polarization of the condensed counterions inside the polyelectrolyte might also be significant. The last effect, which has not been reported previously, reduces both the electric force and the hydrodynamic force acting on the polyelectrolyte. Both the direction and the magnitude of the diffusiophoretic velocity of the polyelectrolyte are found to highly depend upon its physical properties. These results provide valuable references for applications such as DNA sequencing and catalytic nano- or micromotors.

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Diffusiophoresis of Concentrated Suspensions of Liquid Drops

Cited by 29 publications

References 36 publications

Diffusiophoresis of an Elongated Cylindrical Nanoparticle along the Axis of a Nanopore

Diffusiophoresis of an Elongated Cylindrical Nanoparticle along the Axis of a Nanopore

Diffusiophoresis of a Highly Charged Soft Particle in Electrolyte Solutions

Diffusiophoresis of a polyelectrolyte in a salt concentration gradient

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