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December 4, 2000
Q&A:
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Brian Humphrey
professor, Chemistry and Biochemistry
We learned in basic chemistry that plastic does not conduct electricity. Yet
the Nobel Prize in Chemistry this year was awarded to Drs. Alan MacDiarmid,
Alan Heeger and Hideki Shirakawa for discovering that plastic can be made electronically
conductive. Three Nobel Laureates were named, but the years of work that went
into this discovery included a handful of scientists, including Montclair State's
own Brian Humphrey. Although the chemist made significant contributions to MacDiarmid's
revolutionary discovery, Humphrey appearsÑat firstÑto take it with a grain of
NaCl. "It's kind of neat to have worked with a Nobel Prize winner," he said
in a casual tone. But the gleam in Humphrey's eyes and the posture he took when
he discussed his part in this Nobel Prize-winning research, and the patent that
came from it, were a clear indication how much he enjoys chemistry.
INSIGHT: How did
MacDiarmid discover the electronically conductive polymer?
Humphrey: By accident. He was in a chemistry lab in Japan when Shirakawa was
making a polymer of acetylene. But he got the wrong amount of catalysts in there,
forming something that was pure plastic material that looked like aluminum foil.
MacDiarmid invited Shirakawa to the University of Pennsylvania (UP) to work
together to reproduce this particular plasticÑpolyaniline.
INSIGHT: How did
they reproduce it?
Humphrey: One of the most important properties that chemists do not routinely
measure is conductivity. However, physicists do. So MacDiarmid brought in Heeger,
a professor of physics at UP. Between the three of them they figured out how
to change the conductivity of plastic materials by orders of magnitude. It turns
out that plastic is actually more conducting than metal, however, they don't
retain the characteristics of polymers; they turn brittle, just as synthetic
metals do. That's a consequence of the electronic structure of the material.
But people are working on that, too, now. They've increased the flexibility
of the materials and, although it's still not there in terms of replacing metal,
there are a lot of applications that make use of these things, particularly
light-emitting diodes. LEDs used to be primarily red. Now they can be any color,
they're smaller and produce a lot more light.
INSIGHT: How did
you come to work with Dr. MacDiarmid?
Humphrey: I was doing post-doctoral work awarded by the Office of Naval Research
in 1984-85 at MacDiarmid's laboratory at UP. He assigned me and a graduate student
to look at the electrochemistry of polyaniline. We were able to combine what
was already known about its structures to show definitively how those structures
were changing with different electrochemistry. The results were published in
1986 in the Royal Society Faraday Transactions. Of all the publications I've
been in, that was my favorite, because it was a definitive piece of work that
MacDiarmid and I did. We were especially proud because MacDiarmid said it was
the only time he had a paper accepted without revision.
INSIGHT: What became of
your work with MacDiarmid after you came to Montclair State?
Humphrey: In 1986 he was awarded one of the largest grants ever by the U.S.
government, and he asked if I would like to be part of it. For six years we
worked here on that $40,000 grant. It helped a lot of students, and we discovered
that we could combine conducting polymers with cellulose and cellulose containing
polysaccharides, which are biopolymers that are widely used. It was good fundamental
work. A U.S. patent was issued for our work combining conducting polymers with
polysaccharides, and was published in the Journal of the Electric Chemical Society.
INSIGHT: What are
you doing in your lab these days?
Humphrey: I chaired the department from '92-'97, so for the past couple of years
I've been getting back into the laboratory again. It's been fun. I went back
and worked on some of the ideas I had coming out of graduate school, which really
don't have much to do with conducting polymers. I've been making some relatively
large molecules that contain more than one metal center. I draw these rather
striking molecules, and my students are after me to get them on a T-shirt.