The fabrication of structured materials usually can be described as top-down or bottom-up,
reflecting utilization of a lithographic patterning approach or self-assembly technique,
respectively. The self-assembly of smaller objects into larger entities is particularly attractive
due to the anticipated capacity to form three-dimensional structures rapidly and cheaply.
Although self-assembly has proven successful for subunits of nanometer and millimeter
sizes, the fabrication of three-dimensional structures with periodicity on the scale of optical
wavelengths (i.e., micrometer-sized subunits) has been difficult to realize.
Clark et al. describe a hybrid technique using lithographically patterned, 10- to
30-micrometer-sized polyhedral metal plates, the faces of which have been functionalized
with a monolayer of either hydrophobic or hydrophilic molecules. When placed in water
and agitated, the pieces assemble themselves into ordered three-dimensional arrangements.
Controlling the geometry and chemical properties of each face is expected to provide a
broad parameter space that will allow a tailoring of flexibility and the interactions between pieces in the final structure. -- ISO
J. Am. Chem. Soc., 10.1021/ja010641.