By Richard Acello
Small Times Correspondent
SAN DIEGO, Sept. 21, 2001 – With the assistance of the supercomputer at the University of California, San Diego, a team of researchers has used computer simulations to discover carbon fibers with mechanical strength they say is comparable to that of diamond.
In a paper published only six days after the terrorist attack on the World Trade Center, Vincent Crespi Penn State University associate physics professor, said his team had discovered incredibly strong and stiff carbons tubes about 0.4 nanometers in diameter.
To put this in perspective, commercially available carbon fiber is 6 to 10 micrometers thick, or one-fifth the thickness of a human hair. Commercial carbon fibers are used in making everything from golf clubs and tennis rackets to bike frames and yachts.
Carbon nanotubes of the kind discovered by Crespi are 10,000 times thinner than commercial carbon fiber. Crespi said the technology has been used mostly in research to this point, specifically in mapping the position of atoms on a silicon wafer through the use of a “nanowire.”
But Crespi said he is also encouraged by the nanotubes’ potential in the development of low-weight, high-strength materials. Could these nanotubes, for example, result in a bulletproof material? “One could imagine that as a possibility,” he said, “if you could make it in large quantities.”
Supercomputers housed at the University of Michigan and the University of Texas were also used in the research in conjunction with the National Partnership for Advanced Computational Infrastructure (NPACI).
Crespi said the new fiber hasn’t been synthesized yet, but he has spoken with physicists and chemists who are interested. Development of the technology is in the two-to-five-year range, Crespi added.
Crespi’s research is not the only nano-project with anti-terrorism implications in progress at UCSD. Earlier this summer, chemists announced the development of a silicon polymer “nanowire” 2,000 times smaller than the diameter of a human hair.
According to William Trogler, a UCSD chemistry professor, in tests the polymer was able to detect the presence of TNT down to about one part in a billion in air and about 50 parts per billion in seawater. The ongoing research is funded by grants from the Arlington, Va.-based Defense Advanced Research Projects Agency (DARPA) and the National Science Foundation.
“Potentially, it could be used by airlines for screening,” Trogler explained. The polymer could also be deployed as a spray or “sniffer,” that would sample the air around a package, Trogler said, or detect the “vapor coming out of a bomb.”
The polymer is basically a long string of silicon atoms surrounded by molecules that conduct electricity and “glow” under ultraviolet light. Trogler and company modified the polymer to behave like a shorted-out electrical circuit when it comes into contact with TNT, the most commonly used explosive, or picric acid, which has also been used in terrorist attacks.
According to UCSD Professor Michael Sailor, who works with Trogler, the polymers or nanowires can be dissolved in solvents and painted on surfaces, as one would paint a house. Before the World Trade Center attacks, the technology was thought to have its main benefit in detecting unexploded bombs and land mines in the seas. That has changed, and with it possibly the timetable for turning research into products. The typical DARPA project runs on a two-to-five year development cycle, but Trogler said he had been contacted within days of the bombings by an undisclosed company that is interested in commercial development.