Elasticity Mediated Spinner Interaction


Joshua Steimel


Joshua Paul Steimel, Juan Aragones, Alfredo Alexander-Katz

Author Affiliation: 



Active systems are able to exhibit a myriad of non-equilibrium phases and collective dynamical behavior however the origin of such behavior is not well understood. Here we have developed an artificial hybrid active-passive system to investigate the origin of non-equilibrium phase segregation of active and passive components. Dilute concentration of active particles are embedded in dense colloidal monolayer of passive particles in order to study the aggregation of two active particles. Motility is achieved by actuating a rotating magnetic field in the plane of the colloidal monolayer and the active particles, which are ferromagnetic, experience a torque and spin with the rotating field. In the presence of the dense passive monolayer the active particles, or spinners, an ultra-long range attractive force is felt between the spinners leading to aggregation when the spinners are initially 17D apart. In the absence of this passive medium the attraction between spinners is essentially lost. We also show in both simulations and experiments that this attractive force is intimately related to the elasticity of the passive medium and the ability of the spinners to stress the system.