By linking concepts from chemistry and materials science to techniques in fluid mechanics and robotics, we proposed a platform of collective microrobots based on dynamic and programmable self-assembly of circular magnetic micro-rafts at the air-water interface. The cosinusoidal edge-height profiles of these micro-rafts not only create a net dissipative capillary repulsion that is sustained by continuous torque input, but also enables directional assembly of micro-rafts (a – c). We have demonstrated collective behaviors such as channel crossing (d). In addition, in a collaboration with Eric Lauga’s group at the University of Cambridge, we have investigated the mechanism of the interactions between rafts, which will help us to simulate and predict collective behaviors in the future. We anticipate that this dynamic and programmable self-assembled materials system will serve as a model system for studying non-equilibrium dynamics and statistical mechanics as well as for use as a novel platform to assemble and control microrobots in the future.