Practical nanotube fiber near

Spider silk, a product of 400 million years of evolution, stops insects on the wing because it is five times tougher than steel.

Scientists working with carbon nanotubes are looking to surpass the strength of spider line. Nanotubes -- rolled-up sheets of carbon atoms that occur naturally in soot -- also have useful electrical properties.

University of Texas at Dallas researchers have taken a step toward making carbon nanotube fibers manufacturable by speeding up a nanotube fiber-making method 100-fold to produce 70 centimeters of nanotube fiber per minute.

The researchers' 100-meter long fibers are four times tougher than spider silk, and 17 times tougher than the Kevlar fiber used to make bulletproof vests. Toughness is a measure of the energy needed to break a fiber.

The researchers made the fibers by mixing single-walled nanotubes into a rotating solution of polyvinyl alcohol to produce gel fibers. They also formed super capacitors, which store energy, by coating the fibers with an electrolyte.

Antenna, batteries and electromagnetic shields could eventually be made from the fibers, according to the researchers.

The fiber process could be used to manufacture small volumes within a year, according to the researchers. The work appeared in the June 12, 2003 issue of Nature Materials.