Hydrodynamic Signatures of Stationary Marangoni-Driven Surfactant Transport

Bandi, Mahesh; Akella, V. S.; Singh, Dhiraj Kumar; Singh, Ravi Shankar; Mandre, Shreyas

doi:10.1103/physrevlett.119.264501

Cited by 27 publications

(31 citation statements)

References 41 publications

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“…In principle, one should consider two fields, the surface and bulk concentrations, which may locally equilibrate, or not, depending on the kinetic of adsorption and desorption. It is interesting to note, though, that in a recent study of steady Marangoni flows induced by a point source [79,83], the case of camphoric acid is better described by the 2D model, suggesting that such a limiting case could be appropriate for our experimental system. (v) Constant flux.…”

Section: Discussionmentioning

confidence: 99%

Self-propulsion of symmetric chemically active particles: Point-source model and experiments on camphor disks

et al. 2019

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Solid undeformable particles surrounded by a liquid medium or interface may propel themselves by altering their local environment. Such nonmechanical swimming is at work in autophoretic swimmers, whose selfgenerated field gradient induces a slip velocity on their surface, and in interfacial swimmers, which exploit unbalance in surface tension. In both classes of systems, swimmers with intrinsic asymmetry have received the most attention but self-propulsion is also possible for particles that are perfectly isotropic. The underlying symmetry-breaking instability has been established theoretically for autophoretic systems but has yet to be observed experimentally for solid particles. For interfacial swimmers, several experimental works point to such a mechanism, but its understanding has remained incomplete. The goal of this work is to fill this gap. Building on an earlier proposal, we first develop a point-source model that may be applied generically to interfacial or phoretic swimmers. Using this approximate but unifying picture, we show that they operate in very different regimes and obtain analytical predictions for the propulsion velocity and its dependence on swimmer size and asymmetry. Next, we present experiments on interfacial camphor disks showing that they indeed self-propel in an advection-dominated regime where intrinsic asymmetry is irrelevant and that the swimming velocity increases sublinearly with size. Finally, we discuss the merits and limitations of the point-source model in light of the experiments and point out its broader relevance.

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Section: Discussionmentioning

confidence: 99%

Self-propulsion of symmetric chemically active particles: Point-source model and experiments on camphor disks

et al. 2019

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“…We assume that pollutants are advected by the velocity field of the fluid while diffusing with a simple non-dimensional diffusion coefficient . Moreover, we assume that no transport occurs from the surface to the bulk of the flow, so that the bulk concentration can be neglected (Bandi et al 2017). In practice, is limited by chemistry considerations; high values of correspond to a highly polluted surface.…”

Section: Modelling Of Interface Pollutionmentioning

confidence: 99%

Influence of interface pollution on the linear stability of a rotating flow

et al. 2020

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“…23 Previously, it has been showed that below the cmc, the surfactant flow is controlled by both adsorption and surface gradient. 11 In this study, we used twice cmc to ensure the saturation of the surface layer. Hence, the ST at this concentration was used for temperature analysis.…”

Section: Resultsmentioning

confidence: 99%

Influence of Hydrophilicity on the Thermal-Driven Surfactant Flow at the Air/Water Surface

Nguyen

Phan

2018

ACS Omega

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A series of Triton surfactants with increasing number of ethylene oxide (EO) groups were applied to investigate thermal-driven surface flow. It was found that the thermal gradient is proportional to the number of EO groups on the surface. This correlation leads to the linear correlation between the surfactant structure and the driving force of the surface flow. The friction force, in contrast, follows a monotonic but nonlinear correlation with surfactant’s EO groups. The results demonstrate the possibilities to manipulate the surface flow, with potential applications in multiple-phase systems.

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Hydrodynamic Signatures of Stationary Marangoni-Driven Surfactant Transport

Cited by 27 publications

References 41 publications

Self-propulsion of symmetric chemically active particles: Point-source model and experiments on camphor disks

Self-propulsion of symmetric chemically active particles: Point-source model and experiments on camphor disks

Influence of interface pollution on the linear stability of a rotating flow

Influence of Hydrophilicity on the Thermal-Driven Surfactant Flow at the Air/Water Surface

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