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 Unconventional superconductor may be used to create quantum computers of the future
19.02.2018 | Chalmers University of Technology

nachricht Hubble sees Neptune's mysterious shrinking storm
16.02.2018 | NASA/Goddard Space Flight Center

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: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Contacting the molecular world through graphene nanoribbons

19.02.2018 | Materials Sciences

When Proteins Shake Hands

19.02.2018 | Materials Sciences

Cells communicate in a dynamic code

19.02.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>