Video shows nanotube spins as it grows

July 27, 2009

HOUSTON -- (July 27, 2009) -- New video showing the atom-by-atom growth of carbon nanotubes reveals they rotate as they grow, much like the halting motion of a mechanical clock's second hand. Published online this month by researchers at France's Université Lyon1/CNRS and Houston's Rice University, the research provides the first experimental evidence of how individual carbon atoms are added to growing nanotubes.

"The key issue for realizing the potential of carbon nanotubes has always been better control of their growth," said team lead Stephen Purcell of the Université Lyon1/CNRS. "Our findings offer new insights for better measurement, modeling and control of nanotube growth."

Carbon nanotubes are long, hollow cylinders of pure carbon. They are hair-like in shape but are about 100,000 times smaller than human hair. They are also about six times stronger than steel, conduct electricity as well as copper and are almost impervious to radiation and chemical destruction. As a result, scientists are keen to use them in superstrong, "smart" materials, but they need to better understand how to produce them.

"The images from Dr. Purcell's lab show the atom-by-atom 'self assembly' of a nanotube," said Rice co-author Boris Yakobson, professor in mechanical engineering and materials science and of chemistry. "The video offers compelling evidence of the rotational motion that accompanies nanotube growth. It brings to mind Galileo's famous quote, 'And yet, it does turn.'"

In February, Yakobson offered a new theory suggesting that nanotubes grow like tiny, woven tapestries, with new atoms attaching to twisting atomic threads. The new video appears to support the theory, indicating that atoms are added in pairs as the tube spins and grows.

To create the images, Purcell's team at LPMCN (Laboratoire de Physique de la Matière Condensée et Nanostructures) used a field emission microscope (FEM). A few atoms of metal catalyst were placed on the tip of the FEM's needle-like probe, and carbon nanotubes grew atop the metal catalyst. An electric current was passed lengthwise through the probe and nanotube, and it projected a bright, top-down image of the nanotube onto a phosphor screen. The bright spot was filmed by a video camera, which revealed the nanotube's rotation during growth.

In one case, a nanotube turned approximately 180 times during its 11-minute growth. A frame-by-frame analysis of the video showed that the rotation proceeded in discrete steps -- much like the halting motion of the second hand on a mechanical clock -- with about 24 steps per rotation.

"The results support our predictions of how nanotubes grow," Yakobson said. "The video shows rotational movement during growth, as carbon atoms are added in pairs to the twisting, chiral network of carbon atoms that comprise the nanotube."
-end-
Co-authors include Mickaël Marchand, Catherine Journet, Dominique Guillot and Jean-Michel Benoit, all of Université Lyon. The research was supported by the Programme en Nanosciences et Nanotechnologies of France's L'Agence Nationale de Recherche, the National Science Foundation and the Air Force Research Laboratory.

Rice University

Related Carbon Nanotubes Articles from Brightsurf:

How plantains and carbon nanotubes can improve cars
Researchers from the University of Johannesburg have shown that plantain, a starchy type of banana, is a promising renewable source for an emerging type of lighter, rust-free composite materials for the automotive industry.

New production method for carbon nanotubes gets green light
A new method of producing carbon nanotubes -- tiny molecules with incredible physical properties used in touchscreen displays, 5G networks and flexible electronics -- has been given the green light by researchers, meaning work in this crucial field can continue.

Growing carbon nanotubes with the right twist
Researchers synthetize nanotubes with a specific structure expanding previous theories on carbon nanotube growth.

Research shows old newspapers can be used to grow carbon nanotubes
New research has found that old newspaper provide a cheap and green solution for the bulk production of single walled carbon nanotubes.

Clean carbon nanotubes with superb properties
Scientists at Aalto University, Finland, and Nagoya University, Japan, have found a new way to make ultra-clean carbon nanotube transistors with superior semiconducting properties.

Dietary fiber effectively purifies carbon nanotubes
A dietary fiber can help separate out semiconducting carbon nanotubes used for making transistors for flexible electronics.

Why modified carbon nanotubes can help the reproducibility problem
Scientists at Tokyo Institute of Technology (Tokyo Tech) conducted an in-depth study on how carbon nanotubes with oxygen-containing groups can be used to greatly enhance the performance of perovskite solar cells.

Tensile strength of carbon nanotubes depends on their chiral structures
Single-walled carbon nanotubes should theoretically be extremely strong, but it remains unclear why their experimental tensile strengths are lower and vary among nanotubes.

New study reveals carbon nanotubes measurement possible for the first time
Swansea University scientists report an entirely new approach to manipulation of carbon nanotubes that allows physical measurements to be made on carbon nanotubes that have previously only been possible by theoretical computation.

Neural networks will help manufacture carbon nanotubes
A team of scientists from Skoltech's Laboratory of Nanomaterials proposed a neural-network-based method for monitoring the growth of carbon nanotubes, preparing the ground for a new generation of sophisticated electronic devices.

Read More: Carbon Nanotubes News and Carbon Nanotubes Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.