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The
power of plastic
By
Amy Geiszler-Jones
Americans
are used to pulling out the plastic and saying, "Charge it."
For
some scientists, like WSU physicist Pawon Kahol, charging with plastic
has literal meaning.
For
nearly 20 years, Kahol has been researching how certain plastics
conduct electricity.
The
plastics, called conducting polymers, go against the conventional
thinking that plastics, unlike metals, can’t conduct electricity.
In fact, plastic is used as the insulation around copper wires in
ordinary electric cables.
Kahol
predicts that polymers, which can be made cheaply, will revolutionize
the way certain items are manufactured or used.
"I’m
totally convinced that this millennium belongs to the conducting
polymers. We will see these conducting plastics take over because
they’ll be cheap and simple to use," says Kahol, who chairs
WSU’s physics department.
Already
they are being commercially sold as batteries in Japan and as coatings
to prevent metals from rusting.
Photo
by Inside WSU
Physics professor Pawan Kahol, right, holds some revolutionary
plastics known as conducting polymers. Looking on is chemistry
professor Jack McCormick, who has helped develop some of the
polymers Kahol has researched while at WSU.
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Polymers
can make military troops undetectable in infrared, night-vision
situations, says Kahol, who worked for several months testing polymers
for this purpose. Military clothing is dipped into the polymers,
which have been dissolved into a solvent solution, to coat the clothing.
The polymers absorb the infrared, night-vision light.
Other
uses include solar cells, very thin display monitors and as anti-static
layers on items such as computers, which are susceptible to static
buildup.
One
of polymers’ futuristic uses is in the field of molecular electronics.
The memory size and speed of computers today have been enhanced
by technology that allows more and more transistors to be attached
to chips without increasing their size, but "there’s a limit
to this," Kahol says.
"It’ll
have to go down to the molecular level, like the human brain. The
way our brain is set up, each molecule has a role to play. In the
same way, computers will be designed where every molecule knows
what it has to do. Each molecule is like a simple transistor."
With
that kind of technology, computers will become dramatically faster
and smaller. When that occurs, a computer the size of a laptop could
become small enough to fit inside a watch.
Polymers
are essentially molecules that exist in long, chemical chains. Chemists
alter the properties by changing some sequences in the chain. So
far, there are about 10 basic types of polymers, but among those
basic polymers are several variations.
In
the field of polymer research, scientists tend to develop niches,
studying certain characteristics.
Kahol
studies the transport and magnetic properties of polymers in certain
environments. He’s trying to figure out exactly how current
flows through polymers. That’s no simple task when minute changes
in the chain of molecules can alter the polymer’s characteristics.
"Some
of these polymers are behaving like copper, but they are not very
stable," meaning that they degrade when air hits them, he explains.
Kahol
is also an expert in using spin resonance techniques, which allow
him to look at individual defects in polymers. The defects are what
gives them different properties.
Only
two other groups of researchers in the world – at Ohio State
University and the University of California at Santa Barbara –
use the same technique Kahol does to study polymers.
Scientists
from all over the world send him samples. Some of his test samples
are homegrown, too, having been created by Jack McCormick, a WSU
chemistry professor.
The
polymers come in different shapes, textures and colors. Kahol has
one sample, used as an anti-corrosion agent, that looks like shards
of charcoal. Another looks like a swatch of green film, while another
looks like mechanical pencil lead. The diversity of polymers is
what makes them multifunctional.
Kahol
started studying polymers in 1982, a few years after they were discovered
by three scientists who were awarded the Nobel Prize in Chemistry
last year.
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