Shirakawa graduated fromTokyo Institute of Technology (Tokyo Tech) with a bachelor's degree in chemical engineering in 1961, and his doctorate in 1966. Afterward, he obtained the post of assistant in Chemical Resources Laboratory at Tokyo Tech.
While employed as an assistant atTokyo Institute of Technology (Tokyo Tech) in Japan, Shirakawa developedpolyacetylene, which has a metallic appearance. This result interestedAlan MacDiarmid when MacDiarmid visited Tokyo Tech in 1975.
In 1977 they discovered that doping withiodine vapor could enhance the conductivity of polyacetylene. The three scientists were awarded the Nobel Prize in Chemistry in 2000 in recognition of the discovery. With regard to the mechanism of electric conduction, it is strongly believed that nonlinearexcitations in the form ofsolitons play a role.
In 1979, Shirakawa became an assistant professor in theUniversity of Tsukuba; three years later, he advanced to a full professor. In 1991 he was appointed as Tsukuba's Chief of Science and Engineering Department of Graduate School (until March, 1993), and as Tsukuba's Chief of Category #3 group (until March, 1997).
Shirakawa's research onconductive polymers can be broken down into four main categories:polyacetylene thin film synthesis, the causation of metallic conductivity due tochemical doping, the creation of conjugated (double or triple bonds in a molecule which are separated by a single bond) liquid crystalline polymers, and acetylene polymerization development that used liquid crystals as solvents.
Polyacetylene Synthesis: Polyacetylene was expected to have certain properties, with insolubility making the substance difficult to work with. Dr. Shirakawa found that polyacetylene thin films can be synthesized, and with the thin films, the doctor clarified the molecular and solidified structures of polyacetylene.
Creation of Metallic Conductivity: Dr. Shirakawa found that, when a trace of a halogen such as bromine or iodine is added to thin film polyacetylene, its electric conductivity increases, and it exhibits metallic conductivity. Shirakawa found that partial electron transfer between dopants and p-electrons of polyacetylene can generate metallic conductivity.
Using Liquid Crystals to Develop Acetylene Polymerization: Dr. Shirakawa developed a method for the production of highly conductive polyacetylene thin films which paralleled the polymerization of acetylene. Furthermore, he succeeded in the synthesis of thin films of helical polyacetylene whose chirality is controllable.
'Chirality:[6] a property of asymmetry, meaning a molecule is distinguishable from itsmirror image; that is, it cannot be superimposed onto it
Creation of Conjugated Liquid Crystalline Polymers: Dr. Shirakawa created self-oriented, conjugated liquid crystalline polymers by introducing liquid crystalline groups into the side chains of p-conjugated polymers such as polyacetylene. He also macroscopically oriented the polymers with electric or magnetic fields and succeeded in having the molecules electric anisotropy.
The general definition of electrical anisotropy describes the variation of an electrical property depending on the lateral or vertical direction (x,y,z) in which a current flows.[7]
Over the years, Shirakawa has expressed that he does not want theNobel Prizes to receive too much special treatment from mass media (especially theJapanese media). He hopes that many vital areas in fields outside the Nobel Prize categories will also become more widely known.[11]
"threatens the pacifist principles and fundamental human rights established by the constitution and should be rejected immediately...(omitted)...Even in difficult times, protecting the freedom of the press, of thought and expression and of academic research is indispensable."[12]
Dr. Shirakawa Hideki. Dr. SHIRAKAWA Hideki - University of Tsukuba. (n.d.). Retrieved December 9, 2022, from https://www.tsukuba.ac.jp/en/about/history/nobel/shirakawa/
