Dispersibility, modified glass beads

The dispersability of PAA modified glass beads composites were examined in different solvents. In polar solvents, such as methanol and acetonitrile, the particles showed good dispersability (Table 1). In non-polar solvents, such as aliphatic and aromatic hydrocarbons, the particles did not disperse very well. The dispersability of the composite particles relates to the hydrophilic/hydrophobic compatibility between PAA on the glass surface and the solvent. 

After an aqueous dispersion of monodispersed spherical colloids was injected into the cell, a positive pressure was applied through the glass tube to force the solvent (water) to flow through the channels. The beads were accumulated at the bottom of the cell, and crystallized into a three-dimensional opaline lattice under continuous sonication. So far, we have successfully applied this approach to assemble monodispersed colloids (both polystyrene beads and silica spheres) into ccp lattices over areas of several square centimeters. This method is relatively fast opaline lattices of a few square centimeters in area could be routinely obtained within several days. This method is also remarkable for its flexibility it could be directly employed to crystallize spherical colloids of various materials with diameters between 200 nm and 10 pm into three-dimensional opaline lattices. In addition, this procedure could be easily modified to crystalhze spherical colloids with diameters as small as 50 nm. ... 

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