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Catalyst-coated, hard particles can spontaneously generate fluid flows, which, in turn, propel the particles through the fluid. If the catalyst-coated object were a deformable sheet, then the self-generated flows could affect not only the sheet’s motion but also its shape. By developing models that capture the interrelated chemical, hydrodynamic, and mechanical interactions, we uncover novel behavior emerging from the previously unstudied coupling between active, soft sheets and the surrounding fluid. The chemically generated flows “sculpt” the sheet into various forms that yield different functionalities, which can be tailored by modifying the sheet’s geometry, patterning the sheet’s surface with different catalysts, and using cascades of chemical reactions. These studies reveal how to achieve both spatial and temporal controls over the position and shape of active sheets and thus use the layers to autonomously and controllably trap soft objects, perform logic operations, and execute multistage processes in fluid-filled microchambers.
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Integrating chemistry, fluid flow, and mechanics to drive spontaneous formation of three-dimensional (3D) patterns in anchored microstructures
Enzymatic reactions in solution drive the convection of confined fluids throughout the enclosing chambers and thereby couple the processes of reaction and convection. In these systems, the energy released from the chemical reactions generates a force, which propels the fluids’ spontaneous motion. Here, we use theoretical and computational modeling to determine how reaction-convection can be harnessed to tailor and control the dynamic behavior of soft matter immersed in solution. Our model system encompasses an array of surface-anchored, flexible posts in a millimeter-sized, fluid-filled chamber. Selected posts are coated with enzymes, which react with dissolved chemicals to produce buoyancy-driven fluid flows. We show that these chemically generated flows exert a force on both the coated (active) and passive posts and thus produce regular, self-organized patterns. Due to the specificity of enzymatic reactions, the posts display controllable kaleidoscopic behavior where one regular pattern is smoothly morphed into another with the addition of certain reactants. These spatiotemporal patterns also form “fingerprints” that distinctly characterize the system, reflecting the type of enzymes used, placement of the enzyme-coated posts, height of the chamber, and bending modulus of the elastic posts. The results reveal how reaction-convection provides concepts for designing soft matter that readily switches among multiple morphologies. This behavior enables microfluidic devices to be spontaneously reconfigured for specific applications without construction of new chambers and the fabrication of standalone sensors that operate without extraneous power sources.
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- Award ID(s):
- 2234135
- PAR ID:
- 10565982
- Publisher / Repository:
- NSF PAR
- Date Published:
- Journal Name:
- Proceedings of the National Academy of Sciences
- Volume:
- 121
- Issue:
- 11
- ISSN:
- 0027-8424
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1073/pnas.2319777121
