This invention relates to processes for the
assembly of three-dimensional structures having periodicities on the scale of optical wavelengths, and at both smaller and larger dimensions, as well as compositions and applications therefore. Invention embodiments involve the
self assembly of three-dimensionally periodic arrays of spherical particles, the
processing of these arrays so that both infiltration and extraction processes can occur, one or more infiltration steps for these periodic arrays, and, in some instances, extraction steps. The product articles are three-dimensionally periodic on a scale where conventional
processing methods cannot be used. Articles and materials made by these processes are useful as thermoelectrics and thermionics, electrochromic display elements, low
dielectric constant electronic substrate materials,
electron emitters (particularly for displays), piezoelectric sensors and actuators, electrostrictive actuators, piezochromic rubbers, gas storage materials,
chromatographic separation materials,
catalyst support materials,
photonic bandgap materials for optical circuitry, and opalescent colorants for the
ultraviolet, visible, and
infrared regions.