Timothy Long, associate professor of chemistry at Virginia Tech, and six other researchers from Virginia Tech, Penn State University, and Cornell University, will use the federal grant to conduct interdisciplinary fundamental research that eventually will lead to the development of new technology for the DOD. The grant provides funding of $3 million over three years, with the possibility of an additional $2 million for two additional years, for a total of $5 million. The program focuses on fundamental breakthroughs, Long said. "It takes our research programs to a new level and to the boundaries of science and engineering. The grant will accelerate our discoveries in nanostructured macromolecular materials."
The fundamental goal of the multidisciplinary research is to investigate how branched macromolecules affect physical properties. Many synthetic macromolecules are linear, Long said, but they can be branched into a comb, brush, or star shape. The researchers will study these branched macromolecules in many ways, such as allowing them to reorganize on demand, and studying these structures in hopes of providing information that will lead to the long-range development of high-tech surfaces and structures. One of the long-range uses of such materials might include military uniforms that are smart enough to cool soldiers in extreme heat and automatically provide a barrier to chemical and biological reagents, Long said. Other applications might include the manufacture of miniaturized machines, displays, sensors, and actuators.
"In Business Week in September 2001, we disclosed our initial efforts involving molecular velcro," Long said. "Other possibilities include macromolecules that are bonded reversibly, or polymers that can be processed more easily, smaller, and with less energy, but have sufficient mechanical properties for many high-performance applications. Such approaches would facilitate the manufacture of miniaturized electronic and optical parts."
The grant, called an Army Research Office Multidisciplinary University Research Initiative, or MURI, is a collaborative venture that brings together chemistry, mechanical engineering, electrical engineering, chemical engineering, and materials science at the participating universities. It not only will serve as a catalyst for research and eventual delivery of new technologies to the DOD, Long said, but also will have a great deal of impact on macromolecular science and engineering education on the Virginia Tech campus.
The collaboration among four departments and two colleges within Virginia Tech, as well as among the various universities, brings a variety of expertise to the project and allows scientists to accomplish more through the synergy of their research, Long said. Some of the projects to be conducted under the MURI program are the following:
•Don Leo of mechanical engineering at Virginia Tech will look at making new materials, called piezo-electric or electro-restrictive materials, that will convert electrical voltage to motion. In studying the relationship between electrical voltage and mechanical energy, Leo will introduce a small voltage on a polymer film to induce motion in the film. This can be useful in the development of miniaturized pumps, valves, wiper blades, security devices and anything that demands very little energy, Long said.
•On the biomedical forefront, Garth Wilkes of chemical engineering at Virginia Tech will research ways to process sub-micron fibers based on branched macromolecules for possible use in many applications, including adhesives, filters, and biomaterials. Micron fibers are about 100th the diameter of a human hair, and Wilkes will be researching how these fibers can be prepared at the molecular level and what applications such fibers might have.
One rapidly emerging application is scaffolding for cell impregnation and tissue growth, Long said. "They also have inherently high surface areas that could scavenge chemical and biological reagents in a very efficient manner," he said. "Biomedical applications could include wound dressings that would contain antibiotics and other therapeutic agents that would be released in a controlled and sustained manner. Or a part of the adhesive bandage with a high surface area might allow the release of molecules to accelerate wound healing." Such biocompatible fibers would help accelerate healing and rapidly seal wounds during emergencies, Long said.
• Another collaboration with Tom Ward in chemistry at Virginia Tech will attempt to develop smart surfaces or adhesives using branched polymers that are responsive to the environment, Long said. This new enabling polymer chemistry could be useful to the military, but also in commercial adaptations, he said. In this project, branched macromolecules would be assembled at a nanomolecular level on a surface so the surface is dynamic and rearranges itself depending on the atmosphere above the surface.
Another use for the military would include "molecular zippers." "If we could encourage multiple layers to more strongly adhere together," Long said, "we could design advanced armor, or lighter clothing that is more resistant to bullets."
•Geoff Coates of Cornell’s chemistry department will focus on branched polyolefins such as polyethylene and polypropylene. The hope is that these efforts will demonstrate that more well-defined branching in low-cost commodity plastics will result in higher performance macromolecules. Branching results in the introduction of more end groups in the macromolecule, and more functionality can be introduced in a controlled fashion. New efficient polymerization catalysts will allow the preparation of these novel materials.
•In the Department of Material Science and Engineering at Penn State University, Ralph Colby studies reology, or flow and the relationship between molecular structure and flow. He will work at both the molecular and applications levels to try to understand the relationship between branched structure and the nature of macromolecular flow. A fundamental understanding of flow permits more facile processing and novel orientation in many nanotechnologies.
•In addition, Rick Claus of electrical engineering at Virginia Tech is working on optical applications of branched macromolecules in an attempt to make more sophisticated electronic and optical devices for military applications, Long said. Such devices might include electrostatic assemblies of functional macromolecules in high-performance protective coatings.
Such future advancements require a multi-disciplinary approach to research and education, Long said, and demand a fundamental understanding of branched macromolecules. "They have asked us to focus on fundamental science and engineering with a keen awareness of defense applications," Long said.
The DOD MURI center will support about 15 graduate students per year and an equal number of undergraduates working together on the research objectives, Long said. "This will influence the education of many students in the next five years and prepare them for successful careers in DOD laboratories," he said. "The DOD would like to attract the best students in the nation. We will increase our students awareness of government career opportunities."
The grant also provides significant opportunities for the development of new instrumentation and analytical capabilities, and student awareness of these laboratory tools is critical to interdisciplinary education, he said.
Contact information:
Timothy Long, telong@vt.edu, 540-231-2480
Richard Claus, roclaus@vte.du, 540-231-7203
Garth Wilkes, gwilkes@vt.edu, 540-231-5498
Don Leo, donleo@vt.edu, 540-231-2917
Tom Ward, tward@vt.edu, 540-231-5867