Look at any electrical cord and you’ll see that it is covered with plastic. Plastic makes an ideal insulator because it’s cheap, flexible, and doesn’t conduct electricity. Or does it? In the late 1970s, three researchers shocked the scientific community by creating plastic that conducts electricity. These scientists – physicist Alan J. Heeger and chemist Alan G. MacDiarmid of the United States, and chemist Hideki Shirakawa of Japan – have been awarded the 2000 Nobel Prize in chemistry.

The discovery of conductive plastics began with a lucky mistake. Plastics are made of organic polymers ? carbon-containing molecules that form long, repeating chains. Shirakawa had been developing thin films from an organic polymer called polyacetylene. One of his laboratory researchers misunderstood his instructions for making the film and added 1000 times too much of the catalyst that triggers the chemical reaction. The result was a new form of polyacetylene: instead of the usual black film, this film was silvery..

Meanwhile, Heeger and MacDiarmid had produced a metallic-looking film of their own, from the inorganic polymer silver nitride. When they learned of Shirakawa’s discovery, they invited him to their lab at the University of Pennsylvania.

In order for a substance to conduct electricity, its electrons must be able to move freely. Plastic does not normally conduct electricity because its electrons are tightly bound to their atoms. The Nobel scientists found they could make polyacetylene conductive by exposing it to iodine vapor. The iodine oxidizes, or removes electrons from, the polyacetylene. Removal of electrons creates a positive charge in the plastic. In effect, it opens up a path so that electric current can pass through. To the surprise of the scientists, modifying the polyacetylene film in this way increased its conductivity by one billion times!

As it turned out, conductive polyacetylene didn’t prove very useful. But researchers around the world have since developed other conductive polymers with a variety of uses. For instance, adding a layer of conductive polymer to photographic film eliminates static electricity that could ruin the film. The polymers have also been used in anti-static carpeting, shields that protect computer screens from electromagnetic radiation, improved TV and video screens, and “smart” windows that keep out sunlight.

In the near future we may have foldable video displays, made from plastics that emit light when excited by an electrical field. Plastic semiconductors aren’t as fast as silicon chips, but may be used in consumer products where low cost is more important than high speed. Conductive polymers are also involved in efforts to develop electronics based on a single molecule. If scientists succeed in developing this technology, we will one day have high-speed computers the size of a wristwatch.

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