Diffusiophoretic Focusing of Suspended Colloids

Shi, Nan; Nery-Azevedo, Rodrigo; Abdel‐Fattah, Amr I.; Squires, Todd M.

doi:10.1103/physrevlett.117.258001

Cited by 88 publications

(107 citation statements)

References 25 publications

(33 reference statements)

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“…3(b) converge on each other and on the yellow line marking the descending front. Similar localisation of particles due to diffusiophoresis is seen in systems where diffusiophoresis is due to salt gradients 24,26,40,41 . There this convergence is called focusing.…”

Section: Diffusiophoresis In a Drying Filmmentioning

confidence: 60%

Stratification of mixtures in evaporating liquid films occurs only for a range of volume fractions of the smaller component

Sear

2018

The Journal of Chemical Physics

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I model the drying of a liquid film containing small and big colloid particles. Fortini et al. [Phys. Rev. Lett. 116, 118301 (2016)] studied these films with both computer simulation and experiment. They found that at the end of drying, the mixture had stratified with a layer of the smaller particles on top of the big particles. I develop a simple model for this process. The model has two ingredients: arrest of the diffusion of the particles at high density and diffusiophoretic motion of the big particles due to gradients in the volume fraction of the small particles. The model predicts that stratification only occurs over a range of initial volume fractions of the smaller colloidal species. Above and below this range, the downward diffusiophoretic motion of the big particles is too slow to remove the big particles from the top of the film, and so there is no stratification. In agreement with earlier work, the model also predicts that large Péclet numbers for drying are needed to see stratification.

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Section: Diffusiophoresis In a Drying Filmmentioning

confidence: 60%

Stratification of mixtures in evaporating liquid films occurs only for a range of volume fractions of the smaller component

Sear

2018

The Journal of Chemical Physics

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“…Diffusiophoresis, which has received recent interest because of experimental and theoretical advances [7][8][9][10][11][12][13][14][15][16][17], refers to the motion of colloidal particles induced by the solute gradients. The local solute gradient gives rise to the particle motion due to the osmotic pressure gradient developed along the particle surface (chemiphoresis) and the liquid junction potential generated by the diffusion of ions with different diffusivities (electrophoresis).…”

mentioning

confidence: 99%

Accumulation of Colloidal Particles in Flow Junctions Induced by Fluid Flow and Diffusiophoresis

et al. 2017

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The flow of solutions containing solutes and colloidal particles in porous media is widely found in systems including underground aquifers, hydraulic fractures, estuarine or coastal habitats, water filtration systems, etc. In such systems, solute gradients occur when there is a local change in the solute concentration. While the effects of solute gradients have been found to be important for many applications, we observe an unexpected colloidal behavior in porous media driven by the combination of solute gradients and the fluid flow. When two flows with different solute concentrations are in contact near a junction, a sharp solute gradient is formed at the interface, which may allow strong diffusiophoresis of the particles directed against the flow. Consequently, the particles accumulate near the pore entrance, rapidly approaching the packing limit. These colloidal dynamics have important implications for the clogging of a porous medium, where particles that are orders of magnitude smaller than the pore width can accumulate and block the pores within a short period of time. We also show that this effect can be exploited as a useful tool for preconcentrating biomolecules for rapid bioassays.

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“…Radically different approaches also focused on the determination of ion repartition at interfaces using transport property characterization. Beyond standard electrokinetic characterization, new electrokinetic properties have been investigated, and in particular the diffusiophoretic [62,63] and diffusioosmotic [6,64] response to ion concentration gradients in solution. Whereas the ζ-potential measured from diffusioosmotic and electroosmotic velocities coincide for KI, LiI and NaI salts in the vicinity of a silica interface [64], discrepancies are observed when considering the diffusioosmotic current of a KCl solution flowing through a membrane formed by boron nitride nanotubes [6].…”

Section: Latest Innovations In Experimental Characterizationmentioning

confidence: 99%

Measuring surface charge: Why experimental characterization and molecular modeling should be coupled

Hartkamp

Biance

et al. 2018

Current Opinion in Colloid & Interface Science

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Surface charge controls many static and dynamic properties of soft matter and micro/nanofluidic systems, but its unambiguous measurement forms a challenge. Standard characterization methods typically probe an effective surface charge, which provides limited insight into the distribution and dynamics of charge across the interface, and which cannot predict consistently all surfacecharge-governed properties. New experimental approaches provide local information on both structure and transport, but models are typically required to interpret raw data. Conversely, molecular dynamics simulations have helped showing the limits of standard models and developing more accurate ones, but their reliability is limited by the empirical interaction potentials they are usually based on. This review highlights recent developments and limitations in both experimental and computational research focusing on the liquid-solid interface. Based on recent studies, we make the case that coupling of experiments and simulations is pivotal to mitigate methodological shortcomings and address open problems pertaining to charged interfaces.

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Diffusiophoretic Focusing of Suspended Colloids

Cited by 88 publications

References 25 publications

Stratification of mixtures in evaporating liquid films occurs only for a range of volume fractions of the smaller component

Stratification of mixtures in evaporating liquid films occurs only for a range of volume fractions of the smaller component

Accumulation of Colloidal Particles in Flow Junctions Induced by Fluid Flow and Diffusiophoresis

Measuring surface charge: Why experimental characterization and molecular modeling should be coupled

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