Collective Transport of Magnetic Microparticles at a Fluid Interface through Dynamic Self-Assembled Lattices

The transport of confined micron-sized particles plays an important role in a range of phenomena in biology, colloidal science, and solid-state physics. Here, an easily implementable strategy that allows for the collective and monitored transport of magnetic colloidal particles along fluid-fluid interfaces is introduced. Adsorbed microparticles are carried on time-dependent magnetic potentials, generated by dynamic self-assembled lattices of different-sized particles confined onto a parallel plane. In such binary system, the synchronized inversion of the precessing applied field allows for the ballistic and directional transport of the motile components along prescribed directions. The transportation mode can be tuned through the stoichiometry or the strength and orientation of the applied field. The described methodology can be used in the capture and manipulation of drugs or pollutants adsorbed on liquid surfaces, the segregation of colloidal mixtures or the assisted mixture of surface active molecules.