Stong nanotubes discovered in supercomputer simulationSan Diego 17 September 2001 A team of researchers lead by Vincent Crespi, the Downsborough Associate Professor of Physics at Penn State University, has used supercomputer simulations to discover carbon fibers with mechanical strength comparable to that of diamond.
In a paper published in
today's Physical Review Letters, Crespi, graduate student Dragan Stojkovic, and
recent Ph.D. graduate Peihong Zhang report that they discovered incredibly
strong and stiff carbon tubes about 0.4 nanometers in diameter. The so-called
nanotubes could theoretically be made from simple starting materials. Using supercomputers at the San Diego Supercomputer Center (SDSC), the
University of Michigan, and the University of Texas, Crespi's team simulated the
electronic states and total energies of various carbon molecules. This
computationally intensive approach to chemistry research at colleges and
universities has been made possible with supercomputers provided by the National
Science Foundation under its National Partnership for Advanced Computational
Infrastructure (NPACI). SDSC, which is on the campus of the University of
California, San Diego, is the leading-edge site for NPACI.
The nanotube discovery by Crespi's team was made serendipitously while its
members were studying unrelated features of carbon compounds. "This is one of
those sideways inspirations that comes when you're looking at one thing and you
suddenly realize it has a different application," said Crespi. He immediately
adjusted the focus of his simulations. "Actually, I was motivated to make this
strong nanotube the moment I realized it could be done."
Commercially available "carbon fiber" is 6 to 10 micrometers thick, or one-fifth
the thickness of a human hair, and made of carbon-containing polymers. It is
used to make items ranging from golf clubs and tennis rackets to bicycle frames
and racing yachts. While this type of carbon fiber is weaker than carbon
nanotubes, it is easy to produce in large quantities. Manufacturers weave it
into sheets, bars, tubes, and other shapes -- often in several overlapping
layers to increase their strength. Binders such as epoxy resins are often
applied to the sheets to connect the fibers to one another for additional
strength.
Carbon nanotubes are 10,000 times thinner than commercial carbon fiber.
Researchers make them using chemical vapor deposition, a standardized industrial
technology in which simple ingredients self assemble. Crespi said vapor
deposition also would most likely be used to make the much stronger version of
nanotube that his group discovered.
Ad Emmen [News on Advanced IT] [Calendar] [Analysis] [IT in Medicine] |
 |