(123a) Collaboration and Competition between Active Sheets for Self-Propelled Particles
AIChE Annual Meeting
2019 AIChE Annual Meeting
Engineering Sciences and Fundamentals
Complex Flows and Soft Mechanics (Invited Talks)
Monday, November 11, 2019 - 12:30pm to 12:55pm
Biological species routinely collaborate for their mutual benefit or compete for available resources, thereby displaying dynamic behavior that is challenging to replicate in synthetic systems. Here, we use computational modeling to design microscopic, chemically active sheets and self-propelled particles encompassing the appropriate synergistic interactions to exhibit bio-inspired âfeedingâ, âfleeingâ and âfightingâ. This design couples two different mechanisms for chemically generating motion in fluid-filled microchambers: solutal buoyancy and diffusiophoresis. Catalyst-coated sheets, which resemble crabs with four distinct âclawsâ, convert reactants in solution into products, and thereby create local variations in the density and chemical composition of the fluid. Via the solutal buoyancy mechanism, the density variations generate fluid flows, which modify the shape and motility of the âcrabsâ. Concomitantly, the chemical variations propel the motion of the particles via diffusiophoresis and thus, the crabsâ and particlesâ motion becomes highly interconnected. For crabs with restricted lateral mobility, these two mechanisms can be modulated to either drive a crab to catch and appear to âfeedâ on all the particles or enable the particles to âfleeâ from this sheet. Moreover, by adjusting the sheetâs size and the catalytic coating, two crabs can compete and âfightâ over the motile, diffusiophoretic particles. Alternatively, the crabs can temporally âshareâ resources by shuttling the particles back and forth between themselves. With completely mobile sheets, four crabs can collaborate to perform a function that one alone cannot accomplish. These findings provide design rules for creating chemically-driven soft robotic sheets that significantly expand the functionality of microfluidic devices.