Templated self-assembly in three dimensions using magnetic levitation (original) (raw)

Although self-assembly (SA) in two dimensions (2D) is highly developed (especially using surfaces as a templates), SA in three dimensions (3D) has been more difficult. This paper describes a strategy for SA in 3D of diamagnetic plastic objects (mm-to cm-sized in this work, but in principle in sizes from ~ 10 µm to m) supported in a paramagnetic fluid by a non-uniform magnetic field. The magnetic field and its gradient levitate the objects, template their selfassembly, and influence the shape of the assembled cluster. The structure of the 3D assembling objects can be further directed using hard mechanical templates-either the walls of the container or co-levitating components-which coincide spatially with the soft template of the magnetic field gradient. Mechanical agitation anneals the levitating clusters; the addition of photocurable adhesive, followed by UV illumination, can permanently fuse components together.