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Experimental observation of flow fields around active Janus spheres.

ABSTRACT: The phoretic mechanisms at stake in the propulsion of asymmetric colloids have been the subject of debates during the past years. In particular, the importance of electrokinetic effects on the motility of Pt-PS Janus sphere was recently discussed. Here, we probe the hydrodynamic flow field around a catalytically active colloid using particle tracking velocimetry both in the freely swimming state and when kept stationary with an external force. Our measurements provide information about the fluid velocity in the vicinity of the surface of the colloid, and confirm a mechanism for propulsion that was proposed recently. In addition to offering a unified understanding of the nonequilibrium interfacial transport processes at stake, our results open the way to a thorough description of the hydrodynamic interactions between such active particles and understanding their collective dynamics.

SUBMITTER: Campbell AI

PROVIDER: S-EPMC6718378 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature

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Experimental observation of flow fields around active Janus spheres.

Campbell Andrew I AI Ebbens Stephen J SJ Illien Pierre P Golestanian Ramin R

Nature communications 20190902 1

The phoretic mechanisms at stake in the propulsion of asymmetric colloids have been the subject of debates during the past years. In particular, the importance of electrokinetic effects on the motility of Pt-PS Janus sphere was recently discussed. Here, we probe the hydrodynamic flow field around a catalytically active colloid using particle tracking velocimetry both in the freely swimming state and when kept stationary with an external force. Our measurements provide information about the fluid ...[more]

PMID: 31477703

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