By sandwiching tiny but super-tough carbon nanotubes between layers of polymer, researchers have created a revolutionary material that is six times stronger than conventional carbon-fibre composites and as hard as some ultrahard ceramic materials used in engineering.
An international team led by Nicholas Kotov of Oklahoma State University in Stillwater say their new material could be used in space engineering or for long-lasting medical implants.
WEST LAFAYETTE, Ind. — Using a more complex system of atoms than carbon nanotubes, scientists at Purdue University have devised a tunable approach to nanotube creation that allows them to build application-specific varieties. Called "rosette nanotubes" and built from a combination of carbon, nitrogen, hydrogen and oxygen, the new structures offer unique physical, chemical and electrical properties, the researchers said.
Duke University researchers may have found a way to fabricate nanotubes with enough consistency for use as electronic circuitry: (same artlcle also here as well)
DURHAM, N.C. -- Duke University chemists report they have made a significant advance toward producing tiny hollow tubes of carbon atoms, called "nanotubes," with electronic properties reliable enough to use in molecular-sized circuits.
In a report posted Oct. 28, 2002, in the online version of the Journal of the American Chemical Society, the Duke group described a method to synthesize starting catalytic "nanocluster" particles of identical size that, in turn, can foster the growth of carbon nanotubes that vary in size far less than those produced previously.
"This is really a first step toward a big future," said Jie Liu, a Duke associate professor of chemistry and the group's leader, of the unprecedented nanotube uniformity they achieved using this process.
Sometimes called "buckytubes," carbon nanotubes' properties were first studied by Japanese researchers in the early 1990s. The nanotubes, measuring just billionths of a meter in diameter (nano means "billionths"), were found to be lightweight but exceptionally strong, with unusual electronic properties.
Depending upon their atomic arrangements, nanotubes can act like conducting metals or like semiconductors, Liu said.
Since microelectronic devices such as computer chips use both semiconductors and metals, researchers foresee nanotubes as the building blocks for even smaller electronic circuitry than the millionths-of-a-meter scale resolutions of today's microchips.
However, "controlling the electronic properties of the nanotubes is becoming the biggest bottleneck that limits the development of nanotube research," Liu said in an interview.
The control problem arises because those electronic properties vary with the way nanotubes' atoms are arranged. And how their atoms are arranged is directly tied to the nanotubes' diameters -- which, until the fabrication advance by Liu and his colleagues, could vary considerably.
|Share |||Randall Parker, 2002 November 01 02:14 PM Materials Advances|