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Y! MyWebRace is on for adhesive that mimicks gecko feet
A UD scientist is part of a team looking to develop a new adhesive.
Saturday, October 11, 2008
DAYTON — Scientists have long been fascinated by the gecko's ability to scurry up walls and across ceilings. Like a tiny Spider-Man, how does the reptile easily lift its feet for movement yet not slip down the wall?
If researchers could develop a material to mimic that directional bond, they could make strong adhesives that fasten and unfasten as swiftly as the gecko moves its feet. Such a material could transform the adhesive market, from sealing packages to bonding airplane parts and, someday perhaps, creating window-clinging suits like Spider-Man's.
The race for the best "gecko foot" dry adhesive escalated this week with a stronger and more practical material developed by a team of researchers from four U.S. institutions, led by the University of Dayton's Liming Dai, who chairs UD's nanomaterials department. The team's findings were reported Friday, Oct. 10, in the journal Science.
In their article, researchers from UD, the Air Force Research Laboratory at Wright-Patterson Air Force Base, the Georgia Institute of Technology and the University of Akron describe an improved carbon nanotube material that, for the first time, creates directionally varied adhesion.
The new material's gripping ability is 10 times stronger than the gecko's and nearly three times stronger than the previous record set by other researchers, according to the report.
Carbon nanotubes are hollow tubes made of carbon atoms, just a millionth of a millimeter in diameter, with extraordinary strength and unique electrical properties. Under a microscope, the nanotubes look a lot like the tiny, sticky hairs on the gecko's feet, Dai said. The tube tips are curly and tangled like spaghetti.
When pressed onto a vertical surface like a wall or window, the tangled portion of the nanotube flattens in contact with the surface, maximizing the attractive force that occurs at the atomic level. When pulled straight away from the surface, however, only the tips of the tangles remain in contact, minimizing the attractive forces.
The carbon nanotubes also conduct heat and electrical current — properties that Dai and his team are looking to enhance for a variety of applications.
For instance, rather than soldering components into electronic devices, modular parts could be easily removed and replaced with the new adhesive. Computers also could be made to disperse heat from their circuits without a fan.
As a dry adhesive, the carbon nanotube material would have many uses in space "where there is a vacuum and traditional kinds of adhesives dry out," Dai said.
The research originated three years ago with funding from the Air Force Research Laboratory, Dai said.
Two years ago, the project won a $1 million grant from the National Science Foundation.
