Vertical cell assembly of colloidal crystal films with controllable thickness

Formation of colloidal crystal films (CCFs) is the first step in the fabrication of inverse colloidal crystals, a class of three-dimensionally ordered, macroporous materials. A new vertical cell assembly method is described that yields CCFs with thicknesses up to 100 µm. The cell consists of two microscope cover glasses separated by a thin polymeric spacer. The lower edge of the cell is placed in a colloidal dispersion. Particles are transported to the top of the cell by capillary force and self-assemble into a CCF as the solvent evaporates. This novel vertical cell assembly method is well suited for fabrication of large area CCFs with controllable thickness that could be further processed into ICC filters for size-based separations of molecules and particles.