Self-reconfiguring active colloidal molecules exhibit autonomous steering and avoidance

Microorganisms possess autonomous navigation and adaptation capabilities that allow them to steer their own motion and further elicit self-avoidance, a crucial strategy for efficient spatial exploration and collective organization. Despite their promise as synthetic counterparts, active colloidal particles lack similar strategies, including internal flexibility and active response to their surroundings. To overcome this limitation, we realize self-reconfiguring active colloidal molecules that self-assemble via purely physical interactions.

Differently from traditional, mechanically preconfigured active particles, spontaneous reconfiguration here decouples reorientation dynamics from rotational diffusivity. Encounters with neighboring molecules furthermore induce rapid reorganization of their internal structure, promoting autonomous steering. This leads molecules to change self-propulsion direction and avoid each other. At high area fractions, the entire system retains a homogeneous structure comprising well-separated active units, thereby maintaining fluidity and allowing for collective rearrangements driven by activity.

This type of collective organization enabled by self-reconfiguration is distinct from dynamic clustering, motility-induced phase separation, or flocking behaviors observed in the case of rigid active particles. Self-reconfiguring active colloidal molecules therefore represent a promising prototype for autonomous motion inside complex environments.