The 2002 Benjamin Franklin Medal in Physics has been awarded to Sumio Iijima of the NEC Corporation in Japan for his discovery of the atomic structure of carbon nanotubes, which are now the subject of vigorous research in condensed matter physics. Meanwhile, John Cahn of NIST in the US receives the Franklin Institute’s Bower Award and Prize for Achievement in Science for his lifelong contribution to materials science. Cahn’s theories are now used in fields as diverse as cosmology and economics.
Iijima discovered carbon nanotubes in 1991 following studies of the structure of graphite – the material from which nanotubes are made – at Cambridge University. After returning to Japan, he established the helical nature of single- and multi-walled nanotubes, and the electrical properties of nanotubes are now under intense scrutiny. Logic gates and single-electron switches are among the latest devices to be made from nanotubes, which could play a key role in a new generation of electronics. Iijima is a professor at Meijo University in Nagoya, Japan, and a Research Fellow at NIST.
Cahn’s career in materials science was sparked by his desire to understand the ‘phase separation’ that takes place during the processing of metal alloys. In this phenomenon, the components of a previously homogeneous mixture separate from each other when the mixture is cooled. Working with John Hilliard in 1961, Cahn developed a generic expression to explain the effect, the well-known Cahn-Hilliard equation.
This equation has since been used to describe many phenomena in physics and chemistry, from the clustering of galaxies in the early universe to the curdling of cream in coffee. It has even been used to develop digital image processing techniques and to explain the distribution of urban populations.
Cahn is now a Senior Fellow in the Materials Science and Engineering Laboratory at NIST. The Bower Award and Prize for Achievement in Science consists of a gold medal and at least $250 000 in cash.
