Pumping and Mixing in Active Pores

Antunes, G. C.; Malgaretti, Paolo; Harting, Jens; Dietrich, S.

doi:10.1103/physrevlett.129.188003

Cited by 10 publications

(8 citation statements)

References 54 publications

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“…Phoretic mechanisms are widely used to actuate transport, be it externally mediated, e.g. by chemo-or electrophoresis, or self-generated: at macroscopic scales, phoresis can drive living organisms and culinary Marangoni cocktails (Mathijssen et al 2022), and in microfluidic environments it can power self-propelled microswimmers like active colloids or droplets (Peddireddy et al 2012;Herminghaus et al 2014;Izri et al 2014;Maass et al 2016;Babu et al 2022;Birrer, Cheon & Zarzar 2022;Dwivedi, Pillai & Mangal 2022;Michelin 2023), or self-driven micropumps for nutrient or fuel mixing and advection in artificial and biological systems (Gilpin, Prakash & Prakash 2017b;Yu et al 2020;Antunes et al 2022). In self-actuated systems, fluid transport is induced through non-equilibrium processes at the interface between the particle and the surrounding fluid where a slip velocity and/or tangential stresses are generated (Anderson 1989).…”

Section: Introductionmentioning

confidence: 99%

Interfacial activity dynamics of confined active droplets

et al. 2023

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Active emulsions can spontaneously form self-propelled droplets or phoretic micropumps. However, it remains unclear how these active systems interact with their self-generated chemical fields, which can lead to emergent chemodynamic phenomena and multistable interfacial flows. Here, we simultaneously measure the flow and chemical concentration fields using dual-channel fluorescence microscopy for active micropumps, i.e. immobilised oil droplets that dynamically solubilise in a supramicellar aqueous surfactant solution. With increasing droplet radius, we observe (i) a migration of vortices from the posterior to the anterior, analogous to a transition from pusher- to puller-type swimmers, (ii) a bistability between dipolar and quadrupolar flows and, eventually, (iii) a transition to multipolar modes. We also investigate the long-time dynamics. Together, our observations suggest that a local build-up of chemical products leads to a saturation of the surface, which controls the propulsion mechanism. These multistable dynamics can be explained by the competing time scales of slow micellar diffusion governing the chemical buildup and faster molecular diffusion powering the underlying transport mechanism. Our results are directly relevant to phoretic micropumps, but also shed light on the interfacial activity dynamics of self-propelled droplets and other active emulsion systems.

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Section: Introductionmentioning

confidence: 99%

Interfacial activity dynamics of confined active droplets

et al. 2023

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“…In this contribution, we briefly review the derivation of the Fick-Jacobs approximation [49][50][51][52][53][54][55][56] and its use in studying transport across corrugated pores and channels. The Fick-Jacobs approximation has been shown to be applicable to the transport of ions [57][58][59][60][61], colloids [62][63][64][65][66], rods [67], polymers [68][69][70], and more recently even active systems [71][72][73], chemial reactors [74] and pattern-forming systems [75].…”

Section: Introductionmentioning

confidence: 99%

Closed formula for the transport of micro-nano-particle across model porous media

Malgaretti¹,

Harting²

2023

Preprint

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In the last decade the Fick-Jacobs approximation has been exploited to capture the transport across constrictions. Here, we review the derivation of the Fick-Jacobs equation with particular emphasis on its linear response regime. We show that for fore-aft symmetric channels the flux of non-interacting systems is fully captured by its linear response regime. For this case we derive a very simple formula that captures the correct trends and that can be exploited as a simple tool to design experiments or simulations. Finally, we show that higher order corrections in the flux may appear for non-symmetric channels.

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“…So, for the above-mentioned case, hydrodynamic interactions seem to mildly affect the Fick–Jacobs approximation. In contrast, the dynamics of confined active systems is very sensitive to their effective hydrodynamic interactions with the channel walls [ 76 , 77 , 78 , 79 ].…”

Section: Introductionmentioning

confidence: 99%

Closed Formula for Transport across Constrictions

Malgaretti

Harting

2023

Entropy

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In the last decade, the Fick–Jacobs approximation has been exploited to capture transport across constrictions. Here, we review the derivation of the Fick–Jacobs equation with particular emphasis on its linear response regime. We show that, for fore-aft symmetric channels, the flux of noninteracting systems is fully captured by its linear response regime. For this case, we derive a very simple formula that captures the correct trends and can be exploited as a simple tool to design experiments or simulations. Lastly, we show that higher-order corrections in the flux may appear for nonsymmetric channels.

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Pumping and Mixing in Active Pores

Cited by 10 publications

References 54 publications

Interfacial activity dynamics of confined active droplets

Interfacial activity dynamics of confined active droplets

Closed formula for the transport of micro-nano-particle across model porous media

Closed Formula for Transport across Constrictions

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