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DIEGO – Touch the tines of a tuning fork and it goes
silent. Scientists have faced a similar problem trying
to harness the strength and conductivity of carbon nanotubes,
regarded as material of choice for the next generation
of everything from biosensors to pollution-trapping
sponges.
Fifield reported the group's
findings today at the American Chemical Society national
meeting. In the decade since the synthesis of the
first carbon nanotubes, researchers have attached
molecules—intended to be the "feelers" for
picking up chemical sensations and passing the information
to the nanotube—using techniques that call for strong
acidity and other harsh conditions that compromise
the material's utility.
"Usually, people use an
organic solution of anchors and incubate the nanotubes
in the solution to deposit the anchors," Fifield
said. "This method allows little control over
the level of anchor loading. Our innovation is the
use of supercritical fluids—carbon dioxide, with both
liquid and gas properties—for anchor deposition."
Their technique allows them "to deposit anchors
on a wide variety of nanotube sample types, including
those not easily incubated in solution," Fifield
said. "It also enables us to control how much
of a nanotube surface is coated with molecules and
the thickness of the coating."
PNNL
(www.pnl.gov) is a DOE Office of Science laboratory
that solves complex problems in energy, national security,
the environment and life sciences by advancing the
understanding of physics, chemistry, biology and computation.
PNNL employs 3,900, has a $650 million annual budget,
and has been managed by Ohio-based Battelle since
the lab's inception in 1965
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