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Spatially Designed Molecular Monolayers in Ordered Nanoscale Materials J. Liu, G. E. Fryxell,(a,b) L.-Q. Wang,(a,b) Y. Shin,(a,b) G. J. Exarhos, and S. Baskaran(a,b) Supported by DOE’s Office of Basic Energy Sciences, Division of Materials Sciences; Office of Environmental Management (EM), Office of Science Laboratory Technology Development (LTR), and the U.S. Department of Agriculture (USDA). (a) EMSL User. (b) Environmental and Health Sciences Division. Tailored nanostructural materials based on self-assembled monolayers of functional molecules on ordered nanoporous substrates have been developed and have shown great potential for breakthrough technologies in environmental remediation, catalytic chemistry, and microelectronic devices. High-quality, close-packed and oriented monolayers can be efficiently assembled in the ordered nanoporous materials. Time dependent high-resolution magnetic resonance technique suggests that the properties of the monolayers, including the cross-link density, and the flexibility of the functional molecules in the porous media, are related to the molecular chain length and to the pore size and shape. Two- or three-dimensional binding sites can also be constructed on the monolayer so that shape and geometry of these molecular binding sites match those of the target molecules or species. Furthermore, using a molecular directed synthesis approach, specific functional molecules can be delivered to a pre-determined site on the monolayer, forming spatially organized molecular monolayers in which the distribution of the functional groups and molecules are tightly controlled. Significance: Nature is abundant with examples in which the distribution of the functional groups and binding sites are tightly controlled on the nanometer scale (e.g., cell membranes, enzymes). This research has pointed to a new direction, not only on how to control the nanoscale ordering, but also on mimicking the sophisticated functionality of natural materials. In addition, the ability to systematically tailor the pore size and specific binding sites in the nanoporous materials promises immediate applications in many areas, including environmental remediation, energy storage and transportation, controlled- and time-release for agriculture and biomedicine. For example, the material works many orders of magnitude better in terms of the loading capacities and kinetics for removing heavy metals from contaminated waste streams, as compared with the best commercial materials on the market. The ability to pack the maximum amount of air in the porosity and to make the surface hydrophobic makes this kind of material a prime candidate as a low dielectric substrate for next generation microelectronics. William R. Wiley Environmental Molecular Sciences Laboratory Feedback: webmaster@emsl.pnl.gov Revised: June 12, 2001 Security & Privacy PNNL-13147