Crystallization of Millimeter-Scale Objects with Use of Capillary Forces

This communication describes the use of self-assembly as a technique for making large, ordered, three-dimensional (3D) arrays of mesoscopic 1 (∼1 mm scale) objects. Its objective is to identify processes and motifs at the mesoscale that can be applied at the microand perhaps nanoscale, and ultimately, to develop processes that can generate functional 3D structures that consist of microand nanoscale components. Three-dimensional structures suggest new interconnect architectures for electronic and optical systems. 2 Existing technologies for making 3D microstructures are limited stereolithography 3 and free-form laser sintering 4 are slow, and traditional casting, machining, and assembly are difficult with small, complex structures or with porous ones. We believe that self-assembly can become a practical strategy for the assembly of large numbers of individual components into ordered aggregates: self-assembling processes operate in parallel, take advantage of cooperative phenomena, and tend to produce structures that are thermodynamic minima and therefore relatively free of defects. 5