Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Like the Famous Doughboy, Nanotubes Give When Poked

18.05.2005


Smaller, faster computers, bullet proof t-shirts and itty-bitty robots, such are the promises of nanotechnology and the cylinder-shaped collection of carbon molecules known as nanotubes. But in order for these exciting technologies to hit the marketplace (who wouldn’t want an itty-bitty robot), scientists must understand how these miracle-molecules perform under all sorts of conditions. For, without nanoscience, there would be no nanotechnology.


Using an atomic force microscope, researchers prodded the nanotubes to see how much they give.



In a recent study, researchers at the Georgia Institute of Technology, along with colleagues from the IBM Watson Research Center and the Ecole Polytechnique Federale de Lausanne in Switzerland, found that while nanotubes are extremely stiff when pulled from the ends, they give when poked in the middle. The larger the radius, the softer they become. The finding, which is important for the development of nanoelectronics, is published in the May 6, 2005 edition of the journal Physical Review Letters.

“We know from previous studies that nanotubes are very stiff in the axial direction (end to end) but very little is known about their radial elasticity, mainly because when you’re working with tubes that small it’s very difficult to poke them without pushing them beyond the point where they will be irremediably damaged,” said Elisa Riedo, assistant professor of physics at Georgia Tech.


Using an atomic force microscope (AFM) and testing it with a tip of 35 nanometers in radius, researchers lightly prodded the nanotubes to measure the elasticity.

“By making a very small indentation in the tubes, we were able to measure the radial elasticity of a number of single and multiwalled carbon nanotubes of different radii. What we found was that as we tested this technique with wider and wider nanotubes, the bigger tubes were much less stiff than the smaller tubes,” said Riedo.

Riedo and colleagues began with a single-walled nanotube with a radius of only 0.2 nanometers and slowly inched, or rather nanometered, their way up to multiwalled nanotubes measuring 12 nanometers in radius. They tested 39 nanotubes in all.

“We started with single-walled nanotubes and then measured tubes with an increasing number of layers, keeping the external radius twice as large as internal radius,” said Riedo. “Our experiments show that for nanotubes with small internal radii, increasing the radii makes them softer. This means that for these tubes, the radial rigidity is controlled by the magnitude of the internal radius, whereas the number of layers plays a minor role.”

But, for the nanotubes with larger radii, the elasticity of the nanotubes is almost constant. This could mean that the softening that occurs as the internal radius of a nanotube is increased, is counterbalanced by the stiffening effect that occurs as the number of layers increases, up to the point at which the nanotube’s properties reach those of graphite, she said.

Understanding just how much these nanotubes of various sizes and layers can bend is an important step in the development of nanoelectronics and the nanowires that carry electrical current through them. Recently, a team of scientists at the University of California, Irvine, demonstrated that transistors made of single-walled nanotubes can operate at much faster speeds than traditional transistors. Knowing just how far these tubes can bend may lead to even more efficient nanowires.

Since the team kept the external radius twice the distance as the tubes’ internal radius in this round of tests, Riedo said the next step is to change this ratio and vary the number of layers, while keeping the internal radius constant and vice-versa to see how these changes affect the tubes’ elastic properties.

David Terraso | EurekAlert!
Further information:
http://www.icpa.gatech.edu

More articles from Physics and Astronomy:

nachricht Observations of nearby supernova and associated jet cocoon provide new insights on gamma-ray bursts
18.01.2019 | George Washington University

nachricht A new twist on a mesmerizing story
17.01.2019 | ETH Zurich Department of Physics

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Ten-year anniversary of the Neumayer Station III

The scientific and political community alike stress the importance of German Antarctic research

Joint Press Release from the BMBF and AWI

The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...

Im Focus: Ultra ultrasound to transform new tech

World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles

The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.

Im Focus: Flying Optical Cats for Quantum Communication

Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.

In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...

Im Focus: Nanocellulose for novel implants: Ears from the 3D-printer

Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.

It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:

Im Focus: Elucidating the Atomic Mechanism of Superlubricity

The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.

One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Our digital society in 2040

16.01.2019 | Event News

11th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Aachen, 3-4 April 2019

14.01.2019 | Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

 
Latest News

Additive manufacturing reflects fundamental metallurgical principles to create materials

18.01.2019 | Materials Sciences

How molecules teeter in a laser field

18.01.2019 | Life Sciences

The cytoskeleton of neurons has been found to be involved in Alzheimer's disease

18.01.2019 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>