Katzenstein Speaker Tells of Imminent
Revolution in Plastic Electronics
Expect to see an explosion of technology based on plastics that conduct electricity some time soon, says Nobel laureate Alan Heeger.
Some conducting polymers could be used to make flexible computer screens; others that are luminescent may help detect substances such as anthrax, Heeger says: "I can just imagine a computer that I can roll up and put in my pocket. That's a revolution."
Heeger, a professor of physics at the University of California, Santa Barbara, was the speaker Nov. 2 in the physics department's annual Katzenstein Distinguished Lecture Series. His contributions to the discovery and development of conductive polymers - plastics that conduct electricity - earned him the 2000 Nobel Prize in Chemistry.
He and his colleagues were awarded the prize for making polymers conductive by removing the hydrogen. Three generations of polymers have previously been marked by Nobel Prizes. Heeger's work helped usher in the fourth generation.
The previous generations of polymers, which didn't conduct, are amazing materials, said Heeger: "Polymers are the most used materials in our lives today. They are strong enough to make bulletproof vests and skis."
Conducting polymers are even more useful, he claimed, because of the qualities they combine. They are as durable and easy to make as plastics, but have a conductivity near that of copper. "Because of the combination of properties," he said, "we are on the verge of a revolution in plastic electronics."
Polymers are very easy to make, he said: "polymerization is like cooking." And the liquid forms of conducting polymers are very versatile, he noted. They can be used to form extremely thin films, for example. Holding up a two-inch vial of a green conducting polymer in liquid form, Heeger said "the material in here is probably enough to cover the campus."
During the lecture, he displayed a variety of applications of luminescent polymers, polymers that give off light as they conduct electricity. One of these was a replica of his Nobel medal, bearing the profile of Alfred Nobel, which glowed green when he turned it on.
He also showed a one-inch square of plastic that glowed bright green when placed on a battery. Polymers are so cheap, he said, that the most expensive component was the glass on which the square was mounted.
And he held up a cellphone with a display that could be clearly seen across the mid-sized lecture hall. Such devices could be commonplace within a year, he said.
Heeger said the liquid forms of luminescent conducting polymers can be thought of as inks. Using something similar to an inkjet printer, the inks could be used to create inexpensive displays with the quality of a laptop screen, simply by printing them onto sheets of plastic. "I want to put these colored inks into an inkjet printer," he said, "and I want to print the electronics."
He said the technology could also be used to make flexible computer screens that could be carried in a pocket.
Heeger said another use of luminescent conducting polymers is to signal the presence of viruses or bacteria. One of his students is developing polymer-based solutions that glow when various germs are introduced to them. This approach could be used to detect anthrax, he said: "I think that they can make a contribution here."
Heeger's work on conducting plastics demonstrates that the first germ of an idea can have widespread applications.
Brent C. Evans