Kōrero: MacDiarmid, Alan Graham

Whārangi 3: Towards the Nobel Prize

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MacDiarmid, Alan Graham

1927–2007

Chemist, scientist

I tuhia tēnei haurongo e Paul Callaghan,, ā, i tāngia tuatahitia i runga i te ipurangi i 2011.

Overseas study

On completion of his Masters degree, MacDiarmid left New Zealand in 1950 on a Fulbright scholarship to the United States, which enabled him to complete a PhD in inorganic chemistry at the University of Wisconsin, under the supervision of Norris Hall. That first PhD concerned the rate of exchange in C-tagged complex metal cyanides. Funded by a New Zealand Shell graduate scholarship, MacDiarmid undertook a second PhD at Cambridge University, England. His thesis on silicon hydrides was supervised by H. J. Emeléus.

Marriage

In Cambridge on 10 July 1954 Alan MacDiarmid married Marian Laurene Mathieu, whom he had first met at an international club dance at the University of Wisconsin. Their marriage lasted 36 years, until Marian’s death in 1990. They had four children: three girls and a boy.

Collaborations

After a short period at the University of St Andrews, Scotland, MacDiarmid joined the faculty of the University of Pennsylvania in 1955. The first 20 years of his work there was on organo-silicon chemistry, for which he received the American Chemical Society Frederic Stanley Kipping Award in Silicon Chemistry in 1971.

In the 1970s he began his collaboration with University of Pennsylvania physicist Alan Heeger, who had come to MacDiarmid to ask him about a recent paper by Mortimer M. Labes on a new conductor, described by Heeger as 'ess-enn-exx' (SNX). MacDiarmid assumed Heeger meant Sn (tin), a conducting metal. Heeger replied that he meant (SN)x (sulphur nitride). MacDiarmid had made the precursor to this sulphur nitride polymer as part of his New Zealand MSc. Thus began the fruitful relationship between the physicist and the chemist that led to the development of halide addition methods for enhancing polymer conductivity, creating electron vacancies in the molecular orbital and freeing up electron transport.

The final phase of MacDiarmid’s work that led to the Nobel began with a visit to Tokyo Institute of Technology in 1975, and MacDiarmid’s meeting with Hideki Shirakawa. Shirakawa was shown MacDiarmid and Heeger’s golden sulphur nitride polymer, while MacDiarmid learned of the silvery polyacetylene accidentally formed by Shirakawa’s assistant as a result of a mistake involving excess catalyst. MacDiarmid recognised immediately that Shirakawa’s polyacetylene was probably conducting and invited him to the University of Pennsylvania so they could work together, applying the Heeger–MacDiarmid method for conductivity enhancement.

Conducting plastics

The collaboration, crucially funded through support by Ken Wynne at the Office of Naval Research, resulted in the increase of polyacetylene conductivity by over a million, making it almost as good as that of metallic copper. The conducting plastics revolution was born, but it was more than two decades before the consequences for new electronics technologies became apparent. In the 2000s conducting polymers were at the heart of flat-screen video displays, new solar cells and flexible, even wearable, electronic circuitry. In 2000 Alan MacDiarmid was awarded the Nobel Prize in Chemistry conjointly with Alan Heeger and Hideki Shirakawa.

Me pēnei te tohu i te whārangi:

Paul Callaghan. 'MacDiarmid, Alan Graham - Towards the Nobel Prize', Dictionary of New Zealand Biography, first published in 2011. Te Ara - the Encyclopedia of New Zealand, https://teara.govt.nz/mi/biographies/6m2/macdiarmid-alan-graham/page-3 (accessed 31 March 2020)