Self-reconfiguring colloidal active matter

Abstract: Cells and microorganisms employ dynamic shape changes to enable steering and avoidance for efficient spatial exploration and collective organization. In contrast, active colloids, their synthetic counterparts, currently lack similar abilities and strategies. Through physical interactions alone, here we create active colloidal molecules that spontaneously reconfigure their structure, unlike traditional active particles. We find that self-reconfiguration decouples reorientational dynamics from rotational diffusivity and bestows our active molecules additional reorientation capabilities. During encounters with neighbors, rapid conformational changes lead to self-steering and avoidance. At higher area fractions, reconfiguration-induced avoidance fully inhibits characteristic dynamic clustering, motility-induced phase separation and flocking; instead, the system retains a homogeneous structure comprising well-separated active units. Self-reconfiguring systems therefore present an exciting path towards autonomous motion beyond that of classical synthetic active matter.