Responsive colloidal molecules as reconfigurable microswimmers with programmable multistate dynamics

Contrary to their biological analogs or larger scale robotic systems, artificial microswimmers lack self-regulation and rely on external control to adapt their motion. Finding strategies to endow them with in-built feedback schemes, which couple particle  properties to sensing and self-motility, remains an open challenge. Here, we realize active colloidal clusters with multi-state dynamics. These units are produced via capillary assembly [1] with fine geometrical control, comprising two different PNIPAM thermoresponsive microgels and a hard polystyrene colloid. The active clusters, actuated by AC electric fields, adapt their shape and dielectric properties via a temperature-induced transition upon illumination [2]. Different transition temperatures for the two microgels enable three distinct dynamical states via increasing-intensity light inputs. The sequential reconfiguration of the microgels affects the chirality and persistence of the trajectories, connecting active dynamics to the design of different particle states with tailored adaptive pathways.

[1] S. Ni, et al. Soft Matter, 13, 4252 (2017) 

[2] L. Alvarez, et. al. Nat Comm. 12, 4762 (2021)