Cooperation in a fluid swarm of fuel-free micro-swimmers

Journal Article · Mon Jan 10 00:00:00 EST 2022 · Nature Communications

DOI:https://doi.org/10.1038/s41467-021-27870-9· OSTI ID:1839141

Ben Zion, Matan Yah ; Caba, Yaelin; Modin, Alvin; Chaikin, Paul M.

Abstract While motile bacteria display rich dynamics in dense colonies, the phoretic nature of artificial micro-swimmers restricts their activity when crowded. Here we introduce a new class of synthetic micro-swimmers that are driven solely by light. By coupling a light absorbing particle to a fluid droplet we produce a colloidal chimera that transforms optical power into propulsive thermo-capillary action. The swimmers’ internal drive allows them to operate for a long duration (days) and remain active when crowded, forming a high density fluid phase. We find that above a critical concentration, swimmers form a long lived crowded state that displays internal dynamics. When passive particles are introduced, the dense swimmer phase can re-arrange to spontaneously corral the passive particles. We derive a geometrical, depletion-like condition for corralling by identifying the role the passive particles play in controlling the effective concentration of the micro-swimmers.

• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0000989
• OSTI ID: 1839141
• Journal Information: Nature Communications, Journal Name: Nature Communications Vol. 13 Journal Issue: 1; ISSN 2041-1723
• Publisher: Nature Publishing Group
• Country of Publication: United Kingdom
• Language: English