Colloidal Crystallization in 2D and 3D:
The Quest for Novel Materials
Orlin D. Velev
Department of Chemical Engineering
University of Delaware
Newark, DE 19716
Recent research in the assembly of micrometer and nanometer sized colloidal structures has shown promise for creation of novel materials for high technology applications. This talk summarizes different methods for the assembly of 2D and 3D colloidal crystals onto surfaces or into liquid films. We have characterized the colloidal driving forces and developed methods for 2D crystallization in three complementary systems - wetting films on solid surfaces, films on liquid surfaces, and freely suspended foam films. A major challenge besides understanding and controlling the colloidal assembly is turning the obtained structures into potentially usable materials. Two examples of experimental results in this direction will be presented. First, data on how the 2D crystallization can be used for the fabrication of colloidal particles with complex structure will be shown. The second example will demonstrate how 3D colloidal crystals can be turned into solid-state materials by replicating their structure into silica matrix. By using colloidal crystal templates we have been able to obtain microstructured silica of which the pore size, shape and ordering can be controlled in a wide region that has been previously unattainable. In conclusion, the author's assessment of the trends and the perspectives in the field will be presented.
© Copyright O. D. Velev 1998