Hydrodynamic capture of microswimmers into sphere-bound orbits.
Soft Matter
; 10(11): 1784-9, 2014 Mar 21.
Article
em En
| MEDLINE
| ID: mdl-24800268
ABSTRACT
Self-propelled particles can exhibit surprising non-equilibrium behaviors, and how they interact with obstacles or boundaries remains an important open problem. Here we show that chemically propelled micro-rods can be captured, with little change in their speed, into close orbits around solid spheres resting on or near a horizontal plane. We show that this interaction between sphere and particle is short-range, occurring even for spheres smaller than the particle length, and for a variety of sphere materials. We consider a simple model, based on lubrication theory, of a force- and torque-free swimmer driven by a surface slip (the phoretic propulsion mechanism) and moving near a solid surface. The model demonstrates capture, or movement towards the surface, and yields speeds independent of distance. This study reveals the crucial aspects of activitydriven interactions of self-propelled particles with passive objects, and brings into question the use of colloidal tracers as probes of active matter.
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Base de dados:
MEDLINE
Assunto principal:
Viscosidade
/
Nanotubos
/
Hidrodinâmica
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article