Conductive polymer Nobel laureate Hideki Shirakawa dies at 90

Hideki Shirakawa, whose work helped overturn the view that plastics do not conduct electricity, has died at 90, an obituary published by Nature on 11 November 2026, said. He shared the 2000 Nobel Prize in Chemistry with Alan MacDiarmid and Alan Heeger for work on conductive polymers.

Shirakawa showed that thin films of polyacetylene, a polymer made by joining acetylene molecules, could conduct electricity when treated with small amounts of other chemicals. The process is known as doping.

An accidental film

Earlier preparations of polyacetylene produced an insoluble black powder that was difficult to study. In 1967, Shirakawa and visiting researcher Hyung Chick Pyun were trying to make the powder at the Tokyo Institute of Technology when Pyun mistakenly used a catalyst concentration 1,000 times higher than intended. A ragged film formed on the solution’s surface instead.

Shirakawa then made a thin film with a metallic shine by introducing acetylene gas into a flask coated inside with concentrated catalyst. The film looked metallic but was not a good electrical conductor on its own.

Making the film conduct

MacDiarmid invited Shirakawa to the University of Pennsylvania, where Shirakawa spent a year from September 1976. Working with MacDiarmid and Heeger, he found that adding small amounts of molecules that accept or donate electrons increased the film’s electrical conductivity by a factor of 10 million. Electron transfer between the added chemicals and polyacetylene can produce metallic conductivity.

Obituary author Kazuo Akagi, a research professor at Ritsumeikan University and professor emeritus at Kyoto University and the University of Tsukuba, worked with Shirakawa on polyacetylene films after joining his University of Tsukuba laboratory in 1984. Akagi credited Shirakawa’s discovery with leading to new materials, light-emitting diodes and solar cells.