Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Rice engineers make first pure nanotube fibers

10.12.2003


This image shows a liquid crystalline solution of sulfuric acid and SWNTs. The solution contains roughly 5.5 percent SWNTs by volume; acid dispersions have resulted in over an order of magnitude improvement in concentration over all previously documented methods.


Discovery could allow industrial production of cables, sheets of pure carbon nanotubes

Researchers at Rice University have discovered how to create continuous fibers of out of pristine single-walled carbon nanotubes. The process, which is similar to the one used to make Kevlar® on an industrial scale, offers the first real hope of making threads, cables and sheets of pure carbon nanotubes (SWNTs).

The research is available online today from the journal Macromolecules.



Scientists estimate nanotubes are about 100 times stronger than steel at one-sixth the weight. By comparison, Kevlar® -- the fiber used in bulletproof body armor -- is about five times stronger than an equal weight of steel. So far, no large-scale objects have been made of pure nanotubes due to a lack of processing methods that are viable on an industrial scale.

Rice’s team believes they have overcome the major hurdle to industrial production of macroscale SWNT objects -- finding a way to store large amounts of nanotubes in liquid form. By dissolving nanotubes in strong sulfuric acid, a team of chemists and chemical engineers was able to achieve solutions containing up to 10 percent by weight of pure carbon
nanotubes -- more than 10 times the highest concentrations
previously achieved. This new processing route uses no polymeric
additives or detergents, which were used in previous processing
methods and are known to be an obstacle to commercial scalability and final product purity.

"As the concentration increases, the nanotubes first align themselves into spaghetti-like strands and eventually they form tightly packed liquid crystals that can be processed into pure fibers," said researcher Matteo Pasquali, assistant professor of chemical engineering.

Nanotubes are hollow cylinders of pure carbon that are just one atom thick. In addition to being very strong, nanotubes can also be either metals or semi-conductors, which means they could be used to manufacture materials that are both "smart" and ultrastrong. NASA, for example, is researching how nanotubes could be use in aircraft and spacecraft.

Chemically, carbon nanotubes are difficult to work with. They are strongly attracted to one another and tend to stick together in hairball-like clumps. Scientists have developed ways to untangle and sort nanotubes, but storing them after processing is difficult. To date, the medium of choice has been detergent and water solutions that contain less than 1 percent of dispersed nanotubes by volume and are processed by using polymer solutions. Such concentrations are too low to support industrial processes aimed at making large nanotube fibers. Moreover, scientists haven’t found a way to remove all the soap and polymer and convert the nanotubes back into their pure form.

"To produce large objects out of nanotubes, chemical processes must use a liquid that can disperse large concentrations of pristine tubes," said Pasquali. "Based on our findings, we believe superacids can be used to make macroscale fibers and sheets of nanotubes using methods that are quite similar to those in widespread use by the chemical industry."

The research paper is titled "Phase Behavior and Rheology of SWNTs in Superacids." Pasquali’s co-authors include Richard E. Smalley, University Professor, the Gene and Norman Hackerman Professor of Chemistry and professor of physics; Robert H. Hauge, distinguished faculty fellow; W. Wade Adams, director, Center for Nanoscale Science and Technology; W.E. Billups, professor of chemistry; research scientists Carter Kittrell, S. Ramesh, and Rajesh K. Saini; graduate students Virginia A. Davis, Lars M. Ericson, A. Nicholas G. Parra-Vasquez, Hua Fan, and Yuhuang Wang, and undergraduate students Valentin Prieto and Jason A. Longoria.



###
This research was funded by the Office of Naval Research, NASA, the Robert A. Welch Foundation and the Nanoscale Science and Engineering Initiative of the National Science Foundation.

The paper is available online at:
http://pubs3.acs.org/acs/journals/toc.page?incoden=mamobx&indecade=0&involume=0&inissue=0.

Jade Boyd | EurekAlert!
Further information:
http://pubs3.acs.org/acs/journals/toc.page?incoden=mamobx&indecade=0&involume=0&inissue=0
http://chico.rice.edu/

More articles from Materials Sciences:

nachricht Research finds new molecular structures in boron-based nanoclusters
13.07.2018 | Brown University

nachricht 3D-Printing: Support structures to prevent vibrations in post-processing of thin-walled parts
12.07.2018 | Fraunhofer-Institut für Produktionstechnologie IPT

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Behavior-influencing policies are critical for mass market success of low carbon vehicles

17.07.2018 | Power and Electrical Engineering

Plant mothers talk to their embryos via the hormone auxin

17.07.2018 | Life Sciences

Subaru Telescope helps pinpoint origin of ultra-high energy neutrino

16.07.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>