(379a) Reconfigurable Paramagnetic Colloidal Microswimmers Using Time-Varying Magnetic Fields

Here we present a microswimmer consisting of paramagnetic colloids connected with magnetically actuated “hinges.” When placed in an eccentric magnetic field, these simple microswimmer can be directed in a controllable manner. Additional components can be added to create a multibody microswimmer, whereby the particles act cooperatively and translate in a given direction. This colloidal version of collective motion mimics a breaststroke, whereby colloidal arms sweep near one side of colloidal torsos without breaking fluid surface. Interestingly, this motion is highly dependent on thermal forces, as Brownian motion is able to change the locomotive speed at low Reynolds numbers. This work offers insight into directing the motion of collective active systems with novel time-varying magnetic fields.