Yuntian T. Zhu & Quingwen
Li talk with ScienceWatch.com and answer a few
questions about this month's Fast Breaking Paper in the
field of Materials Science, general. The authors have
also sent along images of their work.
Article Title: Sustained growth of ultralong carbon
nanotube arrays for fiber spinning
QW;Zhang, XF;DePaula, RF;Zheng, LX;Zhao,
YH;Stan, L;Holesinger, TG;Arendt, PN;Peterson,
Journal: ADVAN MATER
Year: DEC 4 2006
* Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545
* Los Alamos Natl Lab, Los Alamos, NM 87545 USA.
(addresses have been truncated)
Why do you think your paper is highly
This paper reports on the first growth of ultralong (4.7 mm) double wall
carbon nanotube (DWCNT) arrays. The longest CNT array reported previously
was 2.5 mm long.
Long CNT arrays have several advantages over shorter ones in many
applications. For example, longer CNTs, if spinnable, can produce stronger
CNT fibers. We found that DWCNTs grown using our method are more conducive
to spinning. In fact, we have been able to spin CNT fibers from arrays as
long as 1.5 mm. The CNT fibers spun from such long arrays not only have a
much higher specific strength, but also much better conductivity than those
spun from shorter arrays by other groups. Indeed, growing longer CNT arrays
has been a hot topic and many additional papers on this subject have been
published since the publication of our paper in 2006.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
This paper reported on a systematic study of the fast growth of clean, long
DWCNTs. We used a unique technique, ion-beam assisted deposition, to
deposit the buffer layer and catalyst film. We also used a very low
hydrogen concentration in the synthesis of the CNTs, which makes the
process safer and cheaper. The very fast growth also makes the synthesis
conducive to large-scale production.
Would you summarize the significance of your paper in
We've developed a technology that can grow long DWCNTs at a very fast rate.
The nanotube arrays are like a nanotube forest, in which individual
nanotubes stand upright on a substrate. Such long nanotube arrays have
numerous quite advanced applications such as ultrahigh strength fibers
(yarns) for aerospace structure and supercapacitors for energy storage.
How did you become involved in this research, and were
there any problems along the way?
As team leader at the Los Alamos National Lab during this effort to grow
long carbon nanotube arrays for spinning strong nanotube fibers, I’d
like to primarily attribute this important technological breakthrough to
Dr. Qingwen Li, who was a former team member and is now affiliated with the
Suzhou Institute of Nanotech and Nanobionics of the Chinese Academy of
Sciences. Dr. Li was instrumental in developing this technology. Our main
challenges were to optimize the catalyst deposition and, for safety
reasons, to use less hydrogen than other research groups.
Where do you see your research leading in the
The growth of long spinnable arrays has already led to the production of
nanotube fibers that are much stronger per weight than any current
engineering material or fiber. We expect to grow even longer spinnable
nanotube arrays for spinning stronger nanotube fibers (yarns).
Do you foresee any social or political implications for
This technology will have a significant positive impact on society. First,
long nanotube arrays produces ultrastrong fibers that will significantly
improve or revolutionize tens of thousands of products including golf clubs
(sports equipment), armor, and aerospace structures (aircraft, satellites,
launch vehicles) by making them stronger, lighter, safer, and more energy
In fact, a commercial US company, CNT Technologies Inc., in Seattle,
Washington, is currently commercializing this technology. Additionally,
long-length DWCNTs can also be used to make a variety of products including
transparent conducting films, solar cells, and supercapacitors for energy
harvesting and storage, all of which can help solve the global energy
Yuntian T. Zhu, Ph.D.
Department of Materials Science & Engineering
North Carolina State University
Raleigh, NC, USA
Qingwen Li, Ph.D.
Suzhou Institute of Nanotech and Nanobionics
Chinese Academy of Science