Synthesis, Nanoprocessing, and Yarn Application of Carbon Nanotubes

The synthesis of brush-like carbon nanotubes (CNTs), the nanoprocessing, and the application to twisted yarns for CNTs are reviewed. The large-scale synthesis has been established, where 170-mu m-height brush-like CNTs are grown on a 6-in. Si wafer every three minutes. 7-mm-long brush-like CNTs have also been achieved by activating Fe catalysts using H-2 and H2O. It has been observed that the static friction force is proportional to the length of two CNTs that overlaps with a rough surface but does not depend on overlap for CNTs with a smooth surface. The current-induced transformation from elastic bending with buckling to plastic bending has a much higher turn-on current and larger bending angle than those from elastic bend without buckling. The twisted CNT yarns have been spun from the brush-like CNTs. They have a high strength of ca. 4N/tex caused by the surface roughness of CNTs, and their strength is comparable to that of the super strength PE yarns. [DOI: 10.1143/JJAP.47.8149]