Designing Self-propelled, Chemically Active Sheets: Wrappers, Flappers and Creepers

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, 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 employing cascades of chemical reactions. These studies reveal how to achieve both spatial and temporal control over the position and shape of active sheets and thus, utilize the layers to autonomously and controllably trap soft objects, perform logic operations and execute multi-stage processes in fluid-filled microchambers.