AIST Stories No1

From AIST to the Innovative World18Thousand-fold synthetic efficiency!Breakthrough super growth methodCarbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure with a diameter around 1 nm*1 (nanometer) and length of several micrometers (μm) to several millimeters. Single-wall and multi-wall varieties exist, with the walls formed by one-atom-thick sheets of carbon, called graphene (a one-atom thick layer of graphite). Single-wall CNTs are characterized by their dynamic strength of 20-times that of steel, high thermal conductivity on par with diamond, and density half that of aluminum. They are excellent materials in all respects. Application is anticipated in a wide variety of applications where these attributes can be exploited, such as semiconductor elements and electrical wires.Multi-wall CNTs comprising multiple concentric tubes of single-wall CNTs of different diameters are already being manufactured in commercial-scale plants throughout the world and as progress is made in lowering costs, the field is entering a phase of full-fledged market penetration. However, despite an intense global effort spanning many years, the synthesis efficiency for single-wall CNTs that possess superior properties compared with the multi-wall variety remains extremely low and to date, commercial-scale production as a full-fledged industrial material has not come to fruition.Prime Senior Researcher Kenji Hata of the Nanotube Research Center is the person who has changed this situation. In 2004, Hata’s team developed the revolutionary single-wall CNT synthesis technology known as the super growth method.“By adding a trace amount of water during the synthesis of single-wall CNTs, we achieved a more than thousand-fold increase in growth efficiency. Single-wall CNTs synthesized using this method were much purer than previous CNTs, and the specific surface area was at the maximum level for a fibrous substance. Further, as a conductive filler (a material added to confer a certain function), single-wall CNTs possess the maximum aspect ratio*2 (diameter: 3 nm; length: several 100 μm). As such, this material exhibits several excellent features.”Great expectations for a dream material〈21st Century Industrial Revolution〉Prime Senior Researcher, Nanotube Research CenterKenji HataAiming for commercial-scale production and practical usage through development of the super growth method!Development of commercial-scale production technology for single-wall carbon nanotubesCarbon nanotubes (CNT) outperform many existing materials in terms of their strength, lightness, and thermal conductivity. If they can be practically applied as low-cost materials, there is potential for application in all sorts of industries, including buildings with improved resistance to earthquakes, thin and light electrical wires that do not emit heat, and more compact and high-density semiconductor chips; thus, CNTs will probably bring about a revolutionary transformation across the industrial sector.Into the futureAIST!Our life and society will change in this way!