Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Researchers help sort out the carbon nanotube problem

Researchers help sort out the carbon nanotube problem

July 27, 2005

National Institute of Standards and Technology (NIST) and university researchers report a significant step toward sorting out the nanotube “problem” - the challenge of overcoming processing obstacles so that the remarkable properties of the tiny cylindrical structures can be exploited in new polymer composite materials of exceptional strength.

As described in the July 15 issue of Physical Review Letters, (1) their analysis reveals that, during mixing, carbon nanotubes suspended in viscous fluids can be encouraged to sort themselves by length. Achieving uniform sizes of nanotubes is one of several keys to producing affordable, high-quality polymer nanocomposites.

NIST - carbon nanotubes flowing in a polymer
Small- angle neutron scattering pattern provides an inverted representation of how carbon nanotubes flowing in a polymer melt sort themselves by length. Longer nanotubes, which scatter neutrons at lower angles, gather in purple regions, while medium-sized and short nanotubes are indicated by red and yellow, respectively. The dark blue circle in the center of the image is the beam stop, which protects the sensitive detector from the transmitted beam of unscattered neutrons.. Copyright © NIST
Click on image for larger version.

The team found that, under common processing conditions, shorter carbon nanotubes will flow toward the walls of mixing equipment, while the longer tubes tend to congregate in the interior.

Better understanding of factors that promote this self-sorting will point the way to process adjustments and devices that achieve desired arrangements of nanotubes during bulk manufacturing of polymer nanocomposites, says NIST’s Erik Hobbie, leader of the collaboration, which included scientists from the University of Kentucky and Michigan Technical University.

Many times stronger than steel and possessing superlative thermal, optical and electronic properties, nanotubes have been called small-scale wonders, measuring a few nanometers in diameter and ranging greatly in length. Anticipated nanotube-based technologies range from hydrogen storage to transistors to space elevators. Nearest on the horizon are light-weight, high-strength carbon nanotube polymer structural composites.

With lasers, video microscopes and other optical monitoring equipment, the team tracked how nanotubes - both the single-wall and multiwall varieties - behave when suspended, at several different concentrations, in a polymer melt. They analyzed suspensions ranging in viscosity from syrup-like to watery under different mixing conditions.

The results did not suggest a “magic bullet” for getting nanotubes to align uniformly in the same direction - also critical to reliable processing of high-quality nanocomposites. But the finding that, under "modest flow conditions," carbon nanotubes will sort by length could point the way to practical methods for bulk separation of nanotubes according to size.

Further information on nanotube-related research can be found at the Polymers Division Web site at www.nist.gov/polymers.

(1) D. Fry, B. Langhorst, H. Kim, E. Grulke, H. Wang, E.K. Hobbie. Anisotropy of sheared carbon nanotube suspensions. Physical Review Letters, 95, 038304 (July 15, 2005).

####

Contact:
Mark Bello
mark.bello@nist.gov
301-975-3776

Copyright © National Institute of Standards and Technology

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

Possible Futures

Virus structure inspires novel understanding of onion-like carbon nanoparticles April 10th, 2014

Local girl does good March 22nd, 2014

Surface Characteristics Influence Cellular Growth on Semiconductor Material March 12th, 2014

The "Tipping Point" February 12th, 2014

Nanotubes/Buckyballs

High-Performance, Low-Cost Ultracapacitors Built with Graphene and Carbon Nanotubes: Future devices based on technology could bridge gap between batteries and conventional capacitors in portable electronics and hybrid electric vehicles April 23rd, 2014

Amino-functionalized carbon nanotubes act as a carrier for nerve growth factor April 21st, 2014

Effects of Carbon Nanotubes Studied on Pregnant Mothers April 12th, 2014

Nanotech Business Review 2013-2014 April 9th, 2014

Discoveries

University of Tehran Researchers Invent Non-Enzyme Sensor to Detect Blood Sugar April 23rd, 2014

Gold nanoparticles help target, quantify breast cancer gene segments in a living cell April 23rd, 2014

Atomic switcheroo explains origins of thin-film solar cell mystery April 23rd, 2014

Characterizing inkjet inks: Malvern Instruments presents new rheological research April 23rd, 2014

Announcements

Characterizing inkjet inks: Malvern Instruments presents new rheological research April 23rd, 2014

NanoSafe, Inc. announces the addition of the Labconco Protector® Glove Box to its NanoSafe Tested™ registry April 23rd, 2014

Study finds long-term survival of human neural stem cells transplanted into primate brain April 23rd, 2014

High-Performance, Low-Cost Ultracapacitors Built with Graphene and Carbon Nanotubes: Future devices based on technology could bridge gap between batteries and conventional capacitors in portable electronics and hybrid electric vehicles April 23rd, 2014

NanoNews-Digest
The latest news from around the world, FREE







  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE