A unified description of macroion diffusiophoresis, salt osmotic diffusion and collective diffusion coefficient

Annunziata, Onofrio; Fahim, Aisha

doi:10.1016/j.ijheatmasstransfer.2020.120436

Cited by 8 publications

(41 citation statements)

References 69 publications

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“…In the case of charged colloidal dispersions containing both salts and colloids, being able to adjust the distance L between the valves to decouple the diffusion of salts from that of colloids (see Sec. III C) is a major asset not only for measuring the collective diffusion coefficient of dispersions in equilibrium with a reservoir of known ionic content 17 , but also for tackling the complexity of mass diffusion in such systems 69 . Finally, the permeation property of the PDMS matrix of the chip could also be exploited to concentrate solutes in the channel by pervaporation 35 , prior the diffusion experiment triggered by the opening of valve V 2 , see Fig.…”

Section: Discussionmentioning

confidence: 99%

Microfluidic free interface diffusion: Measurement of diffusion coefficients and evidence of interfacial-driven transport phenomena

2022

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We have developed a microfluidic tool to measure the diffusion coefficient $D$ of solutes in an aqueous solution, by following the temporal relaxation of an initially steep concentration gradient in a microchannel. Our chip exploits multilayer soft lithography and the opening of a pneumatic microvalve to trigger the interdiffusion of pure water and the solution initially separated in the channel by the valve, the so called free interface diffusion technique. Another microvalve at a distance from the diffusion zone closes the channel and thus suppresses convection. Using this chip, we have measured diffusion coefficients of solutes in water with a broad size range, from small molecules to polymers and colloids, with values in the range $D \in [10^{-13}- 10^{-9}]$~m$^2$/s. The same experiments but with added colloidal tracers also revealed diffusio-phoresis and diffusio-osmosis phenomena due to the presence of the solute concentration gradient. We nevertheless show that these interfacial-driven transport phenomena do not affect the measurements of the solute diffusion coefficients in the explored concentration range.

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Section: Discussionmentioning

confidence: 99%

Microfluidic free interface diffusion: Measurement of diffusion coefficients and evidence of interfacial-driven transport phenomena

2022

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“…The extension of multicomponent-diffusion studies to mixtures containing macromolecules [ 69 ] or micelles [ 70 ] then prompted more attention to the connection between DLS and multicomponent diffusion. It is now well known that the DLS diffusion coefficient represents the lower eigenvalue of the 2×2 diffusion-coefficient matrix of ternary liquid mixtures of colloidal particles and a cosolute of low molar weight [ 69 , 70 , 71 ].…”

Section: Introductionmentioning

confidence: 99%

“…We know that diffusiophoresis should be regarded as a special case of cross-diffusion [ 71 , 72 ]. It describes the cross-diffusion of a solute that 1) is large compared to the other components of the mixture and 2) is present at low concentration in the mixture.…”

Section: Introductionmentioning

confidence: 99%

“…The following sections of this paper intend to provide a formulation of diffusiophoresis by employing the formalism of multicomponent diffusion and non-equilibrium thermodynamics. Representative experimental diffusiophoresis data previously obtained on two different macromolecules, polyethylene glycol (PEG) [ 25 , 92 , 94 ] and lysozyme [ 66 , 71 , 72 , 95 ], will also be reviewed. These sections will be organized in the following way.…”

Section: Introductionmentioning

confidence: 99%

“…This has been employed to describe the experimental results of PEG. In Section 10 , the experimental results on diffusiophoresis of lysozyme [ 66 , 71 , 72 , 95 ], a positively charged protein, in the presence of salts will be presented. In Section 11 and Section 12 , the experimental results on lysozyme will be discussed by considering both the electrophoretic ( Section 11 ) and preferential-hydration ( Section 12 ) mechanisms responsible for salt-induced protein diffusiophoresis.…”

Section: Introductionmentioning

confidence: 99%

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Diffusiophoresis of Macromolecules within the Framework of Multicomponent Diffusion

Annunziata

2024

Molecules

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Diffusiophoresis is the isothermal migration of a colloidal particle through a liquid caused by a cosolute concentration gradient. Although diffusiophoresis was originally introduced using hydrodynamics, it can also be described by employing the framework of multicomponent diffusion. This not only enables the extraction of diffusiophoresis coefficients from measured multicomponent-diffusion coefficients but also their theoretical interpretation using fundamental thermodynamic and transport parameters. This review discusses the connection of diffusiophoresis with the 2 × 2 diffusion-coefficient matrix of ternary liquid mixtures. Specifically, diffusiophoresis is linked to the cross-term diffusion coefficient characterizing diffusion of colloidal particles due to cosolute concentration gradient. The other cross-term, which describes cosolute diffusion due to the concentration gradient of colloidal particles, is denoted as osmotic diffusion. Representative experimental results on diffusiophoresis and osmotic diffusion for polyethylene glycol and lysozyme in the presence of aqueous salts and osmolytes are described. These data were extracted from ternary diffusion coefficients measured using precision Rayleigh interferometry at 25 °C. The preferential-hydration and electrophoretic mechanisms responsible for diffusiophoresis are examined. The connection of diffusiophoresis and osmotic diffusion to preferential-interaction coefficients, Onsager reciprocal relations, Donnan equilibrium and Nernst–Planck equations are also discussed.

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Enhancing particle segregation in stem wood combustion flue gas wet scrubbers: Experimental investigation of operational conditions

Darbandi,

Risberg,

Westerlund

2024

Case Studies in Thermal Engineering

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A unified description of macroion diffusiophoresis, salt osmotic diffusion and collective diffusion coefficient

Cited by 8 publications

References 69 publications

Microfluidic free interface diffusion: Measurement of diffusion coefficients and evidence of interfacial-driven transport phenomena

Microfluidic free interface diffusion: Measurement of diffusion coefficients and evidence of interfacial-driven transport phenomena

Diffusiophoresis of Macromolecules within the Framework of Multicomponent Diffusion

Enhancing particle segregation in stem wood combustion flue gas wet scrubbers: Experimental investigation of operational conditions

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