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Hideki Shirakawa

( Chemist, Nobel Prize in Chemistry 2000)

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Biography Hideki Shirakawa
Shirakawa, Hideki (Shirakawa, Hideki) (p. 1936). Nobel Prize in Chemistry 2000, (with A. Higuero and A.Mak-Diarmidom).
Born August 20, 1936 in Tokyo, the third child and daughter of a doctor Hatzutaru Fuyuno Buddhist priest, who had 5 children. Family many times changed its domicile, but in 1944, by the end of the war, settled in the small town of Takayama (known as 'small Quito') on the island of Honshu. Since the 3rd grade of elementary school to college Shirakawa spent here.

His higher education began at the Tokyo Institute of Technology in 1957, where he completed a dissertation in May 1966. The institute has mastered Shirakawa polymer chemistry, horticulture and electronics. Studies of polymers began in his student time, and to polyacetylene addressed immediately after the thesis defense, in April 1966. He intended to study the mechanism of polymerization in the presence of a catalyst of Ziegler - Natta.

In the early 70's Shirakawa studied exactly this process. As a result, the synthesis of polyacetylene accumulated in the reaction flask in the form of anything unremarkable black powder. Once an intern from his lab accidentally added a thousandfold excess of catalyst compared with its usual amount (in grams instead of milligrams, quantities). To the surprise of the experimenters on the surface of the liquid formed a beautiful silver foil. Immediately came the obvious question: 'If the resulting plastic its luster similar to the metal, if he could, and conduct electricity? ". It appeared, however, that it is not so.

Meanwhile, in Pennsylvania universtete (USA) A.Mak-Diarmid and A. Khiger, were preoccupied with the same problem - the creation of non-metallic conductors of electric current, but on the basis of inorganic. In 1975 Khiger informed Mac-Diarmida of recently published article M. Labesa, in which he described a highly conducting polymer material of general formula (SN) x. It turns out that even in the 1950 Mac-Diarmid to synthesize compound S4N4. At the request of Higuero Mc Diarmid synthesized the compound of formula (SN) x, and they systematically investigated their properties.

During the visit Mac-Diarmida at Kyoto University, where he worked Shirakawa, they exchanged their samples of polyacetylene (CH) x and (SN) x. It was during this visit, and an error trainee Shirakawa, leading to obtaining silver polyacetylene. The scientists were intrigued and decided to join forces. Shirakawa for the year came to Pennsilvansky University, where they were joined Khiger. Already in the first experiment, researchers were able to slightly increase the electrical conductivity of polyacetylene. The method also increases the electrical conductivity of the polymer in 10 000 000 times was surprisingly simple - should only handle a film of the polymer pairs bromine or iodine. Thus was created a polymer that has electrical conductivity of metals.

However, although polyacetylene, prepared in this manner, and is comparable to the electrical conductivity of many metals, unfortunately, it can not be used in practice, tk. in contact with air it quickly loses this ability. As a result, finding the best options were new conjugated polymers, for example, Polypyrrole, polyaniline and Polythiophene.

The idea to combine the ability to light and forming a low proportion of polymers with the electrical conductivity of metals has received intensive development. Since the electrical conductivity can be changed in a wide range of semiconductors to the level of conductive metals, have become apparent potential commercial aspects of use: batteries, capacitors, antistatic, anti-corrosion materials, etc..

Translation of polymers in solid-state - one of the fastest growing areas. This is caused by the recent discovery that some conjugated polymers exhibit electroluminescent properties - they shine when they pass through the electric current. Fluorescent materials may have many uses. Soon you will see their first practical use of light displays, mobile phones and a message board. Not long to wait when they become a reality television screens of the fluorescent plastic.

Process that causes electroluminescence can be called - the absorption of light will create a charge and, consequently, electric current. This is the principle of solar. The advantages of plastics are large and made of a flexible surface which is not difficult and expensive. Solar plastic elements are needed in various areas, and they will have the broadest application in the very near future.

After returning to Japan, Shirakawa worked on clarifying the chemical causes of the emergence of the electrical conductivity of polyacetylene. As a result of his quest, for which he used a wide range of physical methods of investigation (from spectroscopy to measure the effect Messbauera), the cause was found. It was found that the processing of the polymer with iodine formed carbocations associated with p-electrons of the molecule polyacetylene.

In November 1979, Shirakawa joined the Institute of Materials Science University of Tsukuba, where he became a professor. In March 2000, resigned and withdrew from active scientific work.

In 2000, Shirakawa was awarded the Nobel Prize 'for the discovery and development of polymer-conductors', together with A.Mak-Diarmidom and A. Higuero.

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