Title:

Lightweight and Strong Carbon Nanotube Structures - Spinning CNT Webs up to Large-Scale Structures

Speaker:

Prof. Yoku Inoue

Affiliation:

Shizuoka University

When:

Friday, December 3, 2010 at 3:00:00 PM   Add to Calendar

Where:

MRDC Building, Room Conf. Rm. 3515

Host:

Prof. Gleb Yushin
gleb.yushin@mse.gatech.edu
404-385-3261

Abstract

Carbon nanotube (CNT) has been attracting much interest because of its diverse features, such as good electrical properties, high thermal conductivity and high mechanical strength. However short CNTs are not good for industrial process¬es and thus widespread applications are yet to be established. Our group has been focusing on the growth of millimeter-long multi-walled carbon nanotube (MWNT) arrays, and the fabrication of lightweight and strong CNT structures, including fibers, paper sheets and its composites. MWNT arrays are synthesized using a thermal chemical vapor deposition system with FeCl2 and single acetylene gas of acetylene. Densely grown MWNTs are vertically aligned on a substrate. The height of MWNT ar¬ray reaches 4.4 mm in 16 min with the growth rate over 100 μm/min. From our MWNT array samples. CNT webs, which is a two dimensional CNT networks, are easily drawn by pull¬ing out the edge of the array. During drawing, nanotubes are drawn with taking neighbors one after another connected by van der Waals force. MWNTs are highly aligned in the drawing direction. Therefore the nanotube structures, including fi bers and sheets, have anisotropic properties. Our carbon nanotube fibers are made of only MWNTs, and no binder material is used. The achieved fiber strength is 1050 MPa and electrical resistivity is 1-3×10−3 Ω•cm. The ultra-long and highly aligned MWNTs structures have many advantages in CNT composites too. The aligned CNT composites, where polymer is impregnated into the CNT structures, show high strength and stiffness. Using those CNT structures, we are investigating CNT speakers and CNT thermionic electron emitters. The CNT speaker generates sound by thermoacoustic effect, thus no mechanical vibration. The large surface area of the sparse CNT web structure is responsible for rapid repetition of heating and cooling. One of good points of the CNT speaker is a high and broad supersonic output up to 100 kHz. The sound of the speaker is generated by a temperature difference of several tens de¬grees, and by a difference of several hundred degrees a pulsed electron source is obtained by pulsed thermionic emission over 800°C from the spun CNTfi ber. The “CNT web technology” will be a powerful and compatible technology for the CNT-industry.

Biography

Professor Inoue received his Ph.D. in Engineering and his M.S. and B.S in Electronic Engineering from Kobe University, Ja-pan. His professional experience includes Visiting Associate, Electrical Engineering, Caltech, Associate Professor, Faculty of Engineering, Shizuoka University and Research Associate, Faculty of Engineering, Shizuoka University. His research fields are solid state physics and materials science. Recent interests are mass production of ultra-long CNT arrays, development of lightweight, strong, electrical and thermal conductive CNT structures and composites, and application research of the large scale CNT structures.