Wednesday, October 17, 2007Volume 7, Issue 5
Meeting Results
Polymer Research is the Theme at the 2007 Nelson W. Taylor Lecture
The five talks at this year's Taylor Lecture, presented by the Penn State Department of Materials Science and Engineering in memory of Nelson W. Taylor, the former head of the Penn State Department of Ceramics, were tributes to the importance of polymers and polymer research.
The opening talks are traditionally given by Penn State faculty members, followed by the Taylor Lecture, presented by a distinguished invited guest. This year's faculty speakers were Ralph Colby and Qing Wang of Materials Science and Engineering, David Allara of Chemistry, and Scott Milner, an incoming member of the Chemical Engineering faculty recruited from ExxonMobil. The Taylor Lecture was delivered by Distinguished McKnight University Professor Timothy Lodge of the University of Minnesota.
Tim Lodge delivers the 2007 Nelson W. Taylor Lecture in Materials
(photo credit Mike Fleck)
Polymer in both their natural and synthetic forms are part of every facet of our daily lives - a short list includes rubber, plastics, paints, even biological polymers such as proteins and DNA. Polymers are formed from long chains of repeating units called monomers, single molecules that can combine with similar or identical molecules. Polymer research is one of four main fields of materials study in the Department of Materials Science and Engineering, along with ceramics, metals, and electronic and photonic materials.
Ralph Colby is an expert on glass-forming liquids and liquid crystalline polymers. His talk dealt with the attempt to make polymers, which are usually insulators, more efficient ion transports, especially in polymers used for batteries, actuators, and fuel cells. All the solutions would seem to rely on nanostructures that allow ions to move through materials. Success in this attempt could win someone the Nobel Prize, Colby predicted.
Scott Milner's research is in the area of polymer thin films. His talk centered on the behavior of polymer thin films in relation to the glass transition temperature. The operating temperature of a system can change the glass transition temperature, he said. Also, the closer the material of the thin film is to the substrate, the more glassy it will be, and the closer to the free surface, the less glassy.
For Dave Allara, the ultimate goal of studying molecules in confined geometries is to take a single molecule and have it function as a memory circuit or a switch, a research area in which he says there is still great interest, despite many failed attempts. Recently his research has involved gallium arsenide thin films for electronics. In trying to remove surface traps that allow electrons to escape in GaAs, he determined that you cannot get rid of the traps due to the structure. "Subtle details control important device responses," he said.
Qing Wang's research reaches from the nanostructure of polymer materials to the macro level of device engineering. He discussed polymer nanocomposites used for electrical energy storage, and the possibility of using compact, low cost, and high energy polymers for high density capacitors. High temperature polymers in hybrid vehicles are an exciting area of research.
Tim Lodge's 2007 Taylor Lecture was a short course on block copolymers - which in their simplest form are made of two normal polymers linked end to end. Block copolymers self-assemble in three shapes - spheres, tubes, and sheets. More complex block copolymers can be made with three or more different polymers.
The value of block copolymers lies in the ability to control their structure, length, and shape, their sensitivity to external stimuli, tolerance of component heterogeneity (which makes them commercially useful), the free-energy process of their self-assembly, and their easy scalability. Their potential uses are in nanoscale structures for computer memory and in their ability to precisely direct the assembly of nanostructures.
Block copolymers, Lodge said, have seen a tremendous broadening of their importance as shown by the recent increase of journal articles on the subject. This may be due to the much greater ability to control their structures over the past ten years, he hypothesized.
The Taylor Lectures have consistently attracted notable scientists, including Nobel Laureates, to speak at Penn State. Nelson W. Taylor, in whose honor the series was established in 1969, was the individual most responsible for establishing the College of Earth and Mineral Sciences as a major center for ceramic research.
