Navigation Links
True properties of carbon nanotubes measured
Date:8/15/2008

EVANSTON, Ill. --- For more than 15 years, carbon nanotubes (CNTs) have been the flagship material of nanotechnology. Researchers have conceived applications for nanotubes ranging from microelectronic devices to cancer therapy. Their atomic structure should, in theory, give them mechanical and electrical properties far superior to most common materials.

Unfortunately, theory and experiments have failed to converge on the true mechanical properties of CNTs. Researchers at Northwestern University recently made the first experimental measurements of the mechanical properties of carbon nanotubes that directly correspond to the theoretical predictions.

Carbon nanotubes are cylindrical structures usually less than 30 nanometers in diameter and several microns long. Their small size makes them very strong but at the same time quite difficult to test individually; as a result, experiments typically deviate widely from predictions based on quantum mechanics.

"Imaging and measurement resolutions as well as atomic structural ambiguities (defects) obscured the results of most experiments and provided unreliable mechanical predictions," said Horacio Espinosa, a professor of mechanical engineering at Northwestern's McCormick School of Engineering and Applied Science.

Espinosa and his group at Northwestern have resolved these issues using a nanoscale material testing system based on microelectromechanical system (MEMS) technology. This system allows electronic measurements of load and displacement during a test, which is performed inside a transmission electron microscope to provide real-time atomic imaging.

"This method removes all ambiguity from testing results," Espinosa said. "We can be certain of all the quantities we have measured, and the results match quantum mechanics predictions very well."

Espinosa collaborated with George Schatz, Morrison Professor of Chemistry in Northwestern's Weinberg College of Arts and Sciences, as well as with Peter Zapol, a physicist at Argonne National Laboratory. This work is published online in Nature Nanotechnology and will appear in print in the journal's October issue.

Further research also was reported in the same article regarding the effect of electron irradiation on these materials. One would think that irradiation would degrade the atomic structure of the material, but the researchers found the opposite.

"Irradiating a multiwalled carbon nanotube with an intense electron beam actually forms bonds among the shells of the tube. This is like combining multiple nanotubes into one to form a stronger structure," said lead author Bei Peng, who recently received his doctoral degree from Northwestern under Espinosa's supervision.

This phenomenon also has been theorized in the past, and the research confirms that the properties of multiwalled nanotubes can easily and controllably be altered by electron irradiation.

The irradiation work was supplemented by detailed atomistic modeling. Using computer simulations of the atomic structure of the nanotubes, the team of researchers was able to isolate the mechanism of strengthening due to irradiation.

"The same procedure used to strengthen individual multiwalled nanotubes by irradiation may also be used to link together individual nanotubes into a bundle," said Mark Locascio, a doctoral student co-author of the paper.

This mechanism of crosslinking is a promising method for creating much larger nanotube-based structures. When nanotubes are packed together, they typically have very weak interactions along their surfaces; a spun nanotube rope would not be nearly as strong as its nanoscale constituents. However, irradiation may be the key to improving these interactions by inducing covalent bonds between tubes. If the properties of nanotubes can be scaled up to macroscale ropes and fibers, they may become a viable option for any high-strength application. This could include large cables for applications in industry or infrastructure, as well as smaller threads for lightweight woven fabrics, ballistic armors or composite reinforcement.


'/>"/>
Contact: Megan Fellman
fellman@northwestern.edu
847-491-3115
Northwestern University
Source:Eurekalert

Related biology technology :

1. Study reveals principles behind stability and electronic properties of gold nanoclusters
2. Eniva VIBE(R) Nutraceutical Tested at Linus Pauling Micronutrient Research Institute and Found to Possess DNA Protective Properties
3. Physicists discover how fundamental particles lose track of quantum mechanical properties
4. NIST imaging system maps nanomechanical properties
5. Understanding of actuator properties of carbon nanotubes bring micro machines closer
6. New Oral MEK Inhibitor, RDEA119, Shows Favorable Anti-Tumor Properties
7. Isis Awarded $1.5 Million NIH Grant to Improve Chemical Properties of RNAi-Based Therapeutics
8. Carbon Nanoprobes, Inc Announces Production Agreement With Leading MEMS Foundry
9. A phonon floodgate in monolayer carbon
10. Carbon hoofprint: Cows supplemented with rbST reduce agricultures environmental impact
11. LLNL researchers peer into water in carbon nanotubes
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/10/2016)... BOSTON , Feb. 10, 2016  Matchbook, ... sourcing for fast growing biotech companies, announced today ... Senior Procurement Strategic Advisor. Jim brings nearly 25 ... sourcing and procurement, having spent nearly two decades ... Supply Chain/Logistics and Procurement at Genzyme and, most ...
(Date:2/10/2016)... , ... February 10, 2016 , ... ... the International Society of Pharmaceutical Engineering (ISPE) Rocky Mountain Chapter 21st Annual Vendor ... expecting to fill more than 100 tables for its annual event, which will ...
(Date:2/10/2016)... ... February 10, 2016 , ... SonaCare Medical, LLC reports ... program, Sonalink™ remote monitoring. The inaugural launch of this new technology occurred over ... Dr. Samuel Peretsman to a HIFU technical expert at SonaCare Medical headquarters. ...
(Date:2/10/2016)... ... February 10, 2016 , ... Curoverse announced today that the ... provides capabilities for managing and processing genomic and health data at petabyte scale. ... collecting and analyzing genomic data,” said Adam Berrey chief executive officer at Curoverse. ...
Breaking Biology Technology:
(Date:2/5/2016)... DUBLIN , Feb. 5, 2016 /PRNewswire/ ... the addition of the "Global Facial ... offering. --> http://www.researchandmarkets.com/research/5kvw8m/global_facial ) has ... Facial Recognition Market 2016-2020" report to ... Markets ( http://www.researchandmarkets.com/research/5kvw8m/global_facial ) has announced the ...
(Date:2/3/2016)... --> --> Fourth quarter 2015:   ... fourth quarter of 2014. Gross margin was 46% (32). ... Earnings per share increased to SEK 6.39 (loss: 0.49). Cash ... --> --> January to December ... 1,142% compared with 2014. Gross margin was 43% (31). ...
(Date:2/3/2016)... , Feb. 3, 2016 Vigilant Solutions announces ... Department in Missouri solved two ... reader (LPR) data from Vigilant Solutions. Brian ... in which the victim was walking out of a convenience store and witnessed ... next to his vehicle, striking his vehicle and leaving ...
Breaking Biology News(10 mins):