Plastic that conducts electricity
We have been taught that
plastics, unlike
metals, do not conduct electricity. In fact
plastic is used as insulation round the
copper wires in ordinary electric cables.Yet this
year's Nobel Laureates in
chemistry are being rewarded for their revolutionary
discovery that plastic can, after certain modifications, be made electrically conductive.
Plastics are
polymers, molecules that repeat their structure regularly in long chains.
For a polymer to be able to conduct electric current it must consist alternately of
single and double bonds between the
carbon atoms. It must also be "doped", which
means that electrons are removed (through oxidation) or introduced (through
reduction). These "holes" or extra electrons can move along the molecule - it becomes
electrically conductive.
Heeger, MacDiarmid and Shirakawa made their seminal findings at the end of the
1970s and have subsequently developed conductive polymers into a research field of
great importance for chemists as well as physicists. The area has also yielded
important practical applications. Conductive plastics are used in, or being developed
industrially for, e.g. anti-static substances for photographic film, shields for computer
screen against electromagnetic radiation and for "smart" windows (that can exclude
sunlight). In addition, semi-conductive polymers have recently been developed in
light-emitting diodes,
solar cells and as displays in mobile telephones and mini-format
television screens.
Research on conductive polymers is also closely related to the rapid development in
molecular electronics. In the future we will be able to produce transistors and other
electronic components consisting of individual molecules - which will dramatically
increase the speed and reduce the size of our computers. A computer corresponding
to what we now carry around in our bags would suddenly fit inside a watch…
***
Alan J. Heeger, 64, was born in 1936 in Sioux City, Iowa, USA (US citizen). He is
Professor of Physics and Director of the Institute for Polymers and Organic Solids at
the University of California at Santa Barbara.
Alan G MacDiarmid, 73, was born in 1927 in Masterton,
New Zealand (US citizen).
He is Professor of Chemistry at the University of Pennsylvania.
Hideki Shirakawa, 64, was born in 1936 in Tokyo (Japanese citizen). He is Professor
of Chemistry at the Institute of Materials Science, University of Tsukuba,
Japan.
The Prize amount, SEK 9 million, will be shared equally among the Laureates.