Programmable Nanomagnets for Microscopic Self-Assembly

We develop an experimental platform for programmable microscopic magnetic self-assembly. We manufacture these microparticles at the wafer-scale, with the ability to precisely design shapes, magnetic moments, and magnetic interactions. Once released, we drive particles to explore their configuration space by a rotating magnetic field, generating chaotic flows that mix particles and drive assembly at the air-water interface. As a first example, we control self-limiting assembly by designing the shape and net magnetic moment of clusters at various stages in the assembly process. In particular, we show that spontaneous decoupling of the final product from the reaction forms a powerful principle for self-limiting assembly.