From: Dickey, Michael F (michael_f_dickey@groton.pfizer.com)
Date: Thu May 09 2002 - 07:01:36 MDT
Scientists Make Long Nanotubes
http://www.spacedaily.com/news/carbon-02f.html
The researchers from Rensselaer Polytechnic Institute and collaborators at
Tsinghua University in Beijing found that chemical vapor deposition (CVD), a
widely used technique to grow nanotubes, has a high yield of long strands
when a sulfur-containing compound and hydrogen are added to the process.
Troy - May 07, 2002
For the first time, researchers have created a simplified method for making
long, continuous, hair-like strands of carbon nanotubes that are as much as
eight inches in length.
This breakthrough, reported in the May 3 issue of Science, is a first step
toward creating such products as microcables for electrical devices or
mechanically robust electrochemical actuators for artificial muscles.
The researchers from Rensselaer Polytechnic Institute and collaborators at
Tsinghua University in Beijing found that chemical vapor deposition (CVD), a
widely used technique to grow nanotubes, has a high yield of long strands
when a sulfur-containing compound and hydrogen are added to the process.
Researchers have previously created nanotube fibers with more complex
methods, but because CVD is commonly used to make nanotubes, it would be
easily adaptable and more efficient for synthesizing the long strands for
practical applications.
This new method produced nanotubes that measured 20 centimeters, much longer
than conventional nanotubes, said Pulickel Ajayan.
"Carbon nanotubes are generally microns in length, which is not long enough
for any practical purpose," said Ajayan, associate professor of materials
science at Rensselaer Polytechnic Institute in Troy, N.Y.
"We have created strands with nearly aligned nanotubes that are as long as
20 centimeters. The nanotubes are well ordered in these structures and are
self-assembled during the growth process, which means we don't end up with
an unusable lump that looks like cooked spaghetti," he added.
The process could also be an easier alternative to creating high-purity
single-walled nanotube material in general, said Bingqing Wei, a post
doctoral associate of Ajayan's who came to Rensselaer from Tsinghua
University.
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