Tiny tubes touted for tougher designs (Daily Press)
Tiny tubes touted for tougher designs
Locally developed filaments are 20 times stronger than steel — and offer a potential economic boost.
By Dave Schleck, Daily Press
March 29, 2004
NEWPORT NEWS — A refined version of the material in pencil tips could become lightweight, super-strong building blocks of spacecraft, computer electronics and skyscrapers, thanks in part to research at Jefferson Lab in Newport News.
NASA and the Defense Department alike have keen interest in carbon nanotubes, microscopic filaments that are 20 times stronger than steel at one-sixth the weight. Considering it costs about $10,000 a pound to put something into orbit, carbon nanotubes could save the aerospace industry millions of dollars in weight costs.
Now, nanotubes sell for $500 a gram, or about $226,500 a pound. But pounds of nanotubes are hard to come by; they can't be produced easily or in large quantities. Scientists from NASA and the College of William and Mary are trying to improve the process, and a newly upgraded free electron laser at Jefferson Lab might give them the chance to produce the best nanotubes around.
First, the basics on carbon nanotubes. They're rolled-up bits of carbon, the same stuff that's in pencils and one of the most prevalent elements on Earth. A "nano" is one billionth of a meter. That's how small they are: the same size as a strand of DNA.
Scientists first caught a glimpse of them in 1991. You need an electron microscope to see them. They look like little worms or squiggly tubes.
Carbon comprises diamonds, the strongest substance known to man, yet globs of nanotubes look like clumps of soot.
Great conductors of electricity, nanotubes are already found in the lithium batteries used in laptop computers and cell phones. There are 15 commercial nano-tube producers worldwide. Scientists use Jefferson Lab's free electron laser to make the most refined, single-walled nanotubes, which could change the world.
Imagine computers that are a billion times faster than today's silicon-based machines. Racecars strong enough to withstand the worst crashes. Sensors that detect the slightest bit of damage in a plane long before it becomes a safety threat.
Scientists make nanotubes by shooting a high-powered laser at a graphite target inside a special oven. The target spins to prevent the laser from burning a hole in it. The laser reacting with the target creates a plasma plume as hot as the surface of the sun, spraying nanotubes onto a metal plate or cylinder.
"Nanotubes condense out of the plume like rain out of a cloud," said Mike Smith, a NASA Langley aerospace engineer. NASA, the College of William and Mary, Jefferson Lab and the Pentagon support the four-year, $700,000 nano-tube project.
Scientists have to watch the experiment using remote cameras fed into a control room because the laser creates blinding light. Once the laser is off, they scrape out the nanotubes, which are given to NASA and other collaborators for applied experiments.
There will be serious challenges to overcome before we see components made out of single-walled nanotubes, said Brian Holloway, an associate professor with William and Mary's Department of Applied Science.
Past local experiments have produced about 2 grams an hour, not enough to fill a salt shaker. The free electron laser costs about $1,000 an hour to operate.
"We're starting to get economically viable if we can produce 20 grams an hour," Holloway said.
That's why Smith and Holloway are excited about upgrades in June that will make the laser 20 times more powerful, which should spike nanotube production. They want to prove to commercial interests that nanotubes, especially those made with their soon-to-be-patented process, can be a profit-making endeavor.
Just as silicon research turned an undeveloped area of California into Silicon Valley, breakthroughs in collaborative laser research might turn our region into the Nanotube Nexus. Holloway estimates it will be another 20 or 30 years before refined nanotubes make their way into products like computers or tennis rackets.
For now, researchers can't get enough of them, said Mia Siochi of the Advanced Materials and Processing Brach at NASA Langley.
"We are working with grams at a time, but what we really need is kilograms," she said. "If we could only get drums full of these.