Pitt Scientists Probe World's Smallest Test Tubes

PITTSBURGH—University of Pittsburgh researchers have begun to understand why carbon nanotubes, which are shaped like a test tube and measure 1/20th of a millionth of an inch in diameter, will act as a sponge to soak up nearby molecules. This "molecular sponge effect" is the result of strong adsorption forces inside the nanotubes and may have applications in gas masks, environmental cleanup, the purification of chemicals, and drug delivery.

John T. Yates Jr., R.K. Mellon Professor of Chemistry and Physics in the Department of Chemistry, and J. Karl Johnson, associate professor in the Department of Chemical and Petroleum Engineering, will present their research March 30 at the American Chemical Society's 227th national meeting in Anaheim, Calif.

"These newly synthesized carbon nanotubes are one of the most interesting forms of the element carbon," said Yates, director of Pitt's Surface Science Center. "Because of their small size, the nanotubes selectively capture and retain small gas molecules in their interior. The adsorption of a molecule inside another molecule offers unique opportunities for the control of matter on the nanometer scale."

Using infrared spectroscopy, kinetic methods, and modern theoretical methods, Yates, Johnson, and other researchers probed various molecules bound inside and outside the nanotubes. They found that molecules bound inside the nanotubes can be preferentially displaced, and have developed a theoretical understanding of this unexpected effect.

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