Twenty-five years since they were in the same room together at Penn, three honored scientists reunited on their old stomping grounds for a special symposium.

The symposium honoring Nobel laureates Alan MacDiarmid, Alan Heeger and Hideki Shirakawa May 4 and 5 brought them back to Penn’s Laboratory for Research on the Structure of Matter (LRSM), where the three had conducted the work on conducting polymers — plastics that conduct electricity — that earned them the 2000 Nobel Prize in Chemistry.

The event drew more than 125 scientists from the United States and five foreign countries to Penn to discuss the state of conducting-polymer research.

The symposium began with the laureates themselves.

Shirakawa and MacDiarmid gave variations on their 2000 Nobel Prize lectures. Shirakawa began by describing how he developed the silvery polyacetylene film that caught MacDiarmid’s eye by accident.

Shirakawa, now at Tsukuba University in Japan, had been synthesizing polyacetylene powder using a catalyst. But one time he added 1,000 times the amount of catalyst called for and produced a film instead of a powder. Like the powder, the film had rather low conductivity, so he didn’t think much of it at the time. “I hadn’t yet realized that I was sitting next door to conducting polymers,” he said.

Professor of Chemistry MacDiarmid, in his talk, told of the conversation that eventually got Shirakawa to walk next door by coming to Penn for a year. He also noted that one of the most important things the trio learned was how to speak each other’s language.

Physicist Heeger, who was LRSM director at the time and is now at UC-Santa Barbara, said: “We pioneered an intimate cross-disciplinary collaboration. It isn’t often done. You have to devote time and energy to learning new things and have a willingness to reach out.”

Heeger threw away his Nobel script and reminisced on the Nobel ceremony, complete with pictures, a brief summary of conducting-polymer devices now being developed and an examination of some of today’s conducting-polymer research.

All three heaped praise on the National Science Foundation, which funded the LRSM and the symposium, and on the many researchers — those in the audience included — whose work contributed to and built upon their own.