Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Movies show nanotubes bend like sluggish guitar strings

29.06.2006
Rice videotapes single nanotube using standard microscopes, cameras

In an exciting advance in nanotechnology imaging, Rice University scientists have discovered a way to use standard optical microscopes and video cameras to film individual carbon nanotubes – tiny cylinders of carbon no wider than a strand of DNA. The movies show that nanotubes can be "plucked" by individual molecules of water and made to bend like guitar strings.

"Nanotubes are fairly stiff, and when they are long enough, the bombardment by the surrounding water molecules makes them bend in harmonic shapes, just like the string of a guitar or a piano," said lead researcher Matteo Pasquali, associate professor of chemical and biomolecular engineering and chemistry, and co-director of Rice's Carbon Nanotechnology Laboratory.

The results, which are due to appear in an upcoming issue of Physical Review Letters, were published online June 23.

Pasquali said the analogy with stringed instruments doesn't completely fit with the nanoscale world. Unlike the guitar string, for example, the carbon nanotube is plucked randomly in many places at the same time. Also, it cannot resonate like the guitar string because the nanotube has too little mass, and its vibrations die quickly because it's surrounded by viscous liquid.

Carbon nanotubes are hollow, hair-like strands of pure carbon that are 100 times stronger than steel but weigh only one sixth as much. Nanotubes are one nanometer, or one billionth of a meter, wide. Human hair, by comparison, is about 80,000 nanometers wide.

Nanotubes tend to clump together. To isolate individual tubes, Pasquali and doctoral student Rajat Duggal, now a research engineer at General Electric Co., put clumps of tubes into a mixture of water and a soap-like surfactant called sodium dodecyl sulphate, or SDS. When the nanotube clumps were broken apart with ultrasonic sound waves, the SDS surrounded the individual nanotubes and held them apart, in the same way laundry detergent surrounds and separates dirt particles in the wash.

In order to see individual nanotubes with a standard optical microscope, like those found in most biological laboratories, Pasquali and Duggal added a common red fluorescent dye that's often used to stain cells. The dye, which attached itself to the SDS surrounding each nanotube, glows brightly enough to be seen with the naked eye under a microscope.

"I had been working on fluorescence visualization of DNA, and other students in the lab were working on nanotubes," Duggal recalled. "A colleague was disposing of nanotube suspensions after an experiment, and I asked them to spare me a vial so I could try them with an optical microscope. I thought of decorating the nanotubes with a fluorescent dye that would prefer to be with the SDS rather than the water, and when I looked under the microscope – to my delight – I found bright dancing nanotubes."

Duggal said scientists have used electron microscopes to observe the underdamped vibrations of nanotubes in vacuum, but his and Pasquali's technique gives scientists the ability to see how nanotubes behave in liquids in real time.

Pasquali and Duggal videotaped dozens of nanotubes at 30 frames per second. A frame-by-frame analysis of the tapes revealed harmonic bending in several nanotubes that were 3-5 microns long and showed that the measured amplitude of the bending motion is consistent with earlier predictions of Rice materials scientist Boris Yakobson, professor of mechanical engineering and materials science and of chemistry.

Pasquali said the method works with other surfactants and it may be useful for life scientists who want to find out how nanotubes interact with cells, biomolecules and other biological entities.

"Our method doesn't provide the sensitivity or precision you get with the infrared, single-nanotube imaging methods developed last year by Rice chemist Bruce Weisman and doctoral student Dmitri Tsyboulski, but the equipment we need is less expensive," Pasquali said. "It's akin to the difference between playing a Stadivarius and playing a common violin."

Jade Boyd | EurekAlert!
Further information:
http://www.rice.edu/media/nanotubevideo.html
http://www.rice.edu

More articles from Physics and Astronomy:

nachricht Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State

nachricht What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto

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: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>