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:10/11/2017)... , Oct. 11, 2017  VMS BioMarketing, a leading provider ... nationwide oncology Clinical Nurse Educator (CNE) network, which will launch ... for communication among health care professionals to enhance the patient ... office staff, and other health care professionals to help women ... cancer. ...
(Date:10/11/2017)... TX (PRWEB) , ... October 11, 2017 , ... ... August compared the implantation and pregnancy rates in frozen and fresh in ... contribution of progesterone and maternal age to IVF success. , After comparing the ...
(Date:10/10/2017)... CA (PRWEB) , ... October ... ... a development-stage cancer-focused pharmaceutical company advancing targeted antibody-drug conjugate (ADC) therapeutics, today ... of targeted HPLN (Hybrid Polymerized Liposomal Nanoparticle), a technology developed in collaboration ...
(Date:10/10/2017)... 10, 2017 International research firm Parks Associates announced ... at the TMA 2017 Annual Meeting , October 11 in ... residential home security market and how smart safety and security products impact ... Parks Associates: Smart Home ... "The residential security market has ...
Breaking Biology Technology:
(Date:3/30/2017)... March 30, 2017 Trends, opportunities and forecast ... behavioral), by technology (fingerprint, AFIS, iris recognition, facial recognition, ... others), by end use industry (government and law enforcement, ... and banking, and others), and by region ( ... Asia Pacific , and the Rest ...
(Date:3/28/2017)... 2017 The report "Video Surveillance ... Servers, Storage Devices), Software (Video Analytics, VMS), and Service ... Forecast to 2022", published by MarketsandMarkets, the market was ... projected to reach USD 75.64 Billion by 2022, at ... base year considered for the study is 2016 and ...
(Date:3/24/2017)... Controller General of Immigration from Maldives Mr. Mohamed Anwar and ... international IAIR Award for the most innovative high security ePassport and eGates  ... ... Maldives Immigration Controller General, Mr. Mohamed Anwar ... right) have received the IAIR award for the "Most innovative high security ...
Breaking Biology News(10 mins):