Long nanotubes made possible

Published: Saturday 15 June 2002

Clusters of nanotubes (Credit: Rensselaer Polytechnic Institu)for the first time, researchers have simplified the method for making longer and continuous carbon nanotubes.

Nanotubes are tiny hollow tubes of carbon atoms, 10,000 times thinner than a human hair, which are used as minuscule wires or in ultra-small electronic devices.

Researchers from New York-based Rensselaer Polytechnic Institute and Beijing-based Tsinghua University, have now devised a simpler method for making these nanotubes as long as 20 centimetres. They found that chemical vapour deposition (cvd), a technique widely used to grow nanotubes, has a high yield of long strands when a sulphur-containing compound and hydrogen are added to the process.

"By using the new technique, nanotubes which are well ordered in their structures and are self-assembled during the growth process can be produced. This means we don't end up with an unusable lump that looks like cooked spaghetti," says Pulickel Ajayan, an associate professor of materials science at Rensselaer Polytechnic Institute. Researchers had earlier used complex methods for creating long nanotube fibres. The new cvd technique has no such drawbacks.

This breakthrough is the first step towards creating products such as micro-cables for electrical devices. "Conventional nanotubes are generally microns in length, which is not long enough to be used for any practical application. We have created strands with nearly aligned nanotubes that can be used for many purposes," says Ajayan.

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