Chemical design of self-propelled Janus droplets
Solubilizing, self-propelling droplets have emerged as a rich chemical platform for the exploration of active matter, but isotropic droplets rely on spontaneous symmetry breaking to sustain motion. The introduction of permanent asymmetry, e.g., in the form of a biphasic Janus droplet, has not been explored as a comprehensive design strategy for active droplets, despite the widespread use of Janus structures in motile solid particles. Here, we uncover the chemomechanical framework underlying the self-propulsion of biphasic Janus oil droplets solubilizing in aqueous surfactant. We elucidate how droplet propulsion is influenced by the degree of oil mixing, droplet shape, and oil solubilization rates for a range of oil combinations. In addition, spatiotemporal control over droplet swimming speed and orientation is demonstrated through the application of thermal gradients applied via joule heating and laser illumination. Finally, we also explore the interactions between collections of Janus droplets, including the spontaneous formation of spinning multi-droplet clusters.
- Research Organization:
- Johns Hopkins Univ., Baltimore, MD (United States); Pennsylvania State Univ., University Park, PA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); US Army Research Office (ARO)
- Grant/Contract Number:
- SC0010426; SC0020964; W911NF-18-1-0414
- OSTI ID:
- 1977422
- Journal Information:
- Matter (Online), Vol. 5, Issue 2; ISSN 2590-2385
- Publisher:
- Cell Press/ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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