Unraveling Modular Microswimmers: From Self-Assembly to Ion-Exchange Driven Engines
Benno Liebchen, Ran Niu, Thomas Palberg, Hartmut Löwen
(Submitted on 26 Jul 2018)
Active materials contain self-propelled particles and can spontaneously form a plethora of patterns making them attractive candidates for the self-assembly of smart soft materials. One key limitation of our present understanding of these materials hinges on the complexity of the microscopic mechanisms driving its components forward. Here, using analytical theory, simulations and experiments, we explore such a mechanism for a class of active materials, modular microswimmers, which self-assemble from colloids and ion-exchange resins on charged substrates. Our results unveil the self-assembly processes and the working mechanism of the ion-exchange driven engines underlying modular microswimmers, which have so far illusive, even qualitatively. We apply these engines to show that modular microswimmers can circumvent corners in complex environments and to move uphill. Our work closes a central knowledge gap in modular microswimmers and provides a facile route to extract mechanical energy from ion-exchange processes
