Designer Molecules Reach New Heights
Richard Smalley and his colleagues discovered fullerenes serendipitously
while exploring the basic structure and properties of carbon. In
contrast, other NSF-supported investigators deliberately set
out to create novel materials with desirable properties. An
example is Samuel Stupp, currently Professor of Materials Science
at Northwestern University, whose successes while he was at the
University of Illinois at Urbana-Champaign were described by
writer Robert Service in the April 18, 1997 issue of Science magazine.
"Living cells are masters of hierarchical building. For much of their molecular architecture, they first string together amino acids into proteins, then assemble proteins into more complex structures. Chemists have been working to imitate this skill, in the hope of making new materials tailored right down to the arrangement of molecules. Researchers at [the University of Illinois] report taking this assembly process to a new level of sophistication, creating molecules that assemble themselves over several size scales, first forming clusters, then sheets, and, ultimately, thick films. Because the building-block molecules are all oriented in the same direction, the films' properties mirror those of the individual molecules, yielding a bottom surface that's sticky and a top that's slick. This property could make the films useful for everything from anti-icing coatings on airplane wings to anti-blood-clot linings for artificial blood vessels
" More recently, Stupp and his research team have had success using molecular self-assembly to change the properties of polymers. Their self-assembly method has potential for producing extremely strong polymers and polymers with improved optical properties, and it could impact such diverse fields as the plastics industry, medicine, and optical communications.
Other advances in new materials are coming out of NSF-supported basic research in the field of condensed-matter physics. Researchers at the NSF-funded centers at the University of Chicago and Cornell University are investigating the fundamental physical structure and properties of material when it is placed under extreme conditionssuch as low temperature, high pressure, and high magnetic fields. Investigators look at the novel compositions and structures with extraordinary electrical and optical properties, including metals, insulators, semiconductors, crystals, and granular material. They also learn to control that structurefor example, moving electrons around on the surface of the material. Among other applications, this work will be important as engineers work at creating ultra-high performance computer chips. Other researchers at Michigan State University and Northwestern University are also looking at solid-state chemistry and have synthesized metals with highly efficient thermoelectric propertiesthat is, the ability to generate electricity when junctions between the metals are maintained at different temperatures. Thermoelectric materials already are used in space applications, but as they improve they may be useful in environmentally friendly refrigeration, thermal suits for diving, and cooling systems for electronic devices.