Forces that control self-organization of chemically-propelled Janus tori

Journal Article · 05 July 2022 · Communications Physics

DOI: https://doi.org/10.1038/s42005-022-00953-9 · OSTI ID:1978738

Wang, Jiyuan  ^[1]; Huang, Mu-Jie ^[2]; Baker-Sediako, Remmi D. ^[3]; Kapral, Raymond  ^[2]; Aranson, Igor S.  ^[4]

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1. Heilongjiang University of Science and Technology, Harbin (China); University of Toronto, ON (Canada); Univ. of Toronto, ON (Canada)
2. University of Toronto, ON (Canada)
3. Nanoscribe GmbH & Co. KG (Germany)
4. Pennsylvania State University, University Park, PA (United States)

Control of the individual and collective behavior of self-propelled synthetic micro-objects has immediate application for nanotechnology, robotics, and precision medicine. Despite significant progress in the synthesis and characterization of self-propelled Janus (two-faced) particles, predictive understanding of their behavior remains challenging, especially if the particles have anisotropic forms. Here, by using molecular simulation, we describe the interactions of chemically-propelled microtori near a wall. The results show that a torus hovers at a certain distance from the wall due to a combination of gravity and hydrodynamic flows generated by the chemical activity. Moreover, electrostatic dipolar interactions between the torus and the wall result in a spontaneous tilt and horizontal translation, in a qualitative agreement with experiment. Simulations of the dynamics of two and four tori near a wall provide evidence for the formation of stable self-propelled bound states. Our results illustrate that self-organization at the microscale occurs due to a combination of multiple factors, including hydrodynamic, chemical, electrostatic and steric interactions.

• Research Organization: Pennsylvania State University, University Park, PA (United States)
• Sponsoring Organization: Canada Foundation for Innovation; Heilongjiang Provincial Universities; Natural Sciences and Engineering Research Council of Canada (NSERC); USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0020964
• OSTI ID: 1978738
• Journal Information: Communications Physics, Journal Name: Communications Physics Journal Issue: 1 Vol. 5; ISSN 2399-3650
• Publisher: Springer NatureCopyright Statement
• Country of Publication: United States
• Language: English