MacDiarmid, Alan G

(1927–) US chemist: developer of electrically conducting organic polymers.

Born in New Zealand, MacDiarmid studied chemistry there and at Wisconsin and Cambridge before making his career at the University of Pennsylvania at Philadelphia from 1955.

In 1973 he was working with poly(sulphur nitride), a bronze solid consisting of chains of sulphur and nitrogen atoms,–(SN) n–which conducts like a metal, in collaboration with Alan J Heeger (1936–) a US physicist then also working at Philadelphia. Also in the 1970s Hideki Shirakawa (1936–), a Japanese chemist at Tsukuba, Japan, found a new way of making polyacetylene–(CH) n–which is a plastic and a semiconductor. The two teams worked together from 1975, and soon found that doping the polyacetylene with a small amount of iodine enhanced the conductivity by a factor of many millions, comparable with copper or silver. This discovery in 1977 of the first conducting organic polymer has led to exploration of a range of new uses in antistatic films and fabrics, and in display and detection screens and polymer-based electronic circuits which can be smaller and cheaper than existing inorganic (usually silicon) components.

MacDiarmid, Heeger and Shirakawa shared the Nobel Prize for chemistry for 2000 ‘for the discovery and development of conductive polymers’.