Crystallization of Mesoscopic Colloids into 3D Opaline Lattices in Packing Cells Fabricated by Replica Molding

Replica molding against an elastomeric mold has been used to fabricate packing cells to be used for the crystallization of mesoscopic, spherical colloids into three-dimensionally ordered arrays over relatively large areas. The capability and feasibility of this method have been demonstrated by the production of homogeneous, opaline lattices of 255 or 467 nm polystyrene beads over areas as large as ∼0.5 cm2. These 3D crystalline lattices of mesoscopic colloids are useful for fabricating new types of diffractive optical components, for producing porous materials, and for generating photonic bandgap structures. We believe the demonstration of a replica molding procedure for the fabrication of the packing cells should make the crystallization method more useful to those who have no direct access to clean-room facilities.