Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Simulations help explain fast water transport in nanotubes

Photo by L. Brian Stauffer

Narayana R. Aluru, professor of mechanical science and engineering, left, and doctoral student Sony Joseph have discovered the physical mechanism behind the rapid transport of water in carbon nanotubes. Image in background shows the trajectory of water molecules in a carbon nanotube moving in the direction of their orientations due to rotation-translation coupling.
Photo by L. Brian Stauffer

Narayana R. Aluru, professor of mechanical science and engineering, left, and doctoral student Sony Joseph have discovered the physical mechanism behind the rapid transport of water in carbon nanotubes. Image in background shows the trajectory of water molecules in a carbon nanotube moving in the direction of their orientations due to rotation-translation coupling.

Abstract:
By discovering the physical mechanism behind the rapid transport of water in carbon nanotubes, scientists at the University of Illinois have moved a step closer to ultra-efficient, next-generation nanofluidic devices for drug delivery, water purification and nano-manufacturing.

Simulations help explain fast water transport in nanotubes

CHAMPAIGN, IL | Posted on September 16th, 2008

"Extraordinarily fast transport of water in carbon nanotubes has generally been attributed to the smoothness of the nanotube walls and their hydrophobic, or water-hating surfaces," said Narayana R. Aluru, a Willett Faculty Scholar and a professor of mechanical science and engineering at the U. of I.

"We can now show that the fast transport can be enhanced by orienting water molecules in a nanotube," Aluru said. "Orientation can give rise to a coupling between the water molecules' rotational and translational motions, resulting in a helical, screw-type motion through the nanotube," Aluru said.

Using molecular dynamics simulations, Aluru and graduate student Sony Joseph examined the physical mechanism behind orientation-driven rapid transport. For the simulations, the system consisted of water molecules in a 9.83 nanometer long nanotube, connected to a bath at each end. Nanotubes of two diameters (0.78 nanometers and 1.25 nanometers) were used. Aluru and Joseph reported their findings in the journal Physical Review Letters.

For very small nanotubes, water molecules fill the nanotube in single-file fashion, and orient in one direction as a result of confinement effects. This orientation produces water transport in one direction. However, the water molecules can flip their orientations collectively at intervals, reversing the flow and resulting in no net transport.

In bigger nanotubes, water molecules are not oriented in any particular direction, again resulting in no transport.

Water is a polar molecule consisting of two hydrogen atoms and one oxygen atom. Although its net charge is zero, the molecule has a positive side (hydrogen) and a negative side (oxygen). This polarity causes the molecule to orient in a particular direction when in the presence of an electric field.

Creating and maintaining that orientation, either by directly applying an electric field or by attaching chemical functional groups at the ends of the nanotubes, produces rapid transport, the researchers report.

"The molecular mechanism governing the relationship between orientation and flow had not been known," Aluru said. "The coupling occurs between the rotation of one molecule and the translation of its neighboring molecules. This coupling moves water through the nanotube in a helical, screw-like fashion."

In addition to explaining recent experimental results obtained by other groups, the researchers' findings also describe a physical mechanism that could be used to pump water through nanotube membranes in next-generation nanofluidic devices.

Funding was provided by the National Science Foundation and the National Institutes of Health.

Aluru is affiliated with the U. of I.'s Beckman Institute, Micro and Nanotechnology Laboratory, and departments of bioengineering and of electrical and computer engineering.

####

For more information, please click here

Contacts:
James E. Kloeppel
Physical Sciences Editor
217-244-1073


Narayana Aluru
217-333-1180

Copyright © University of Illinois at Urbana-Champaign

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

News and information

Leti and Taiwanese Tech Organizations Sponsoring Workshop in Taipei on MEMS, IoT, Smart Lighting Applications, System Reliability & Security September 28th, 2016

Dr Barbara Armbruster promoted to Worldwide Sales and Marketing Director for XEI Scientific September 27th, 2016

Fighting cancer with sticky nanoparticles September 27th, 2016

Gold nanoparticles conjugated quercetin inhibits epithelial-mesenchymal transition, angiogenesis and invasiveness via EGFR/VEGFR-2 mediated pathway in breast cancer September 27th, 2016

Microfluidics/Nanofluidics

Novel nanoscale detection of real-time DNA amplification holds promise for diagnostics: Research team led by Nagoya University develop a label-free method for detecting DNA amplification in real time based on refractive index changes in diffracted light September 12th, 2016

W.M. Keck Foundation awards Cal State LA a $375,000 research and education grant August 4th, 2016

Researchers invent 'smart' thread that collects diagnostic data when sutured into tissue: Advances could pave way for new generation of implantable and wearable diagnostics July 18th, 2016

Droplets finally all the same size -- in a nanodroplet library June 20th, 2016

Nanotubes/Buckyballs/Fullerenes

Semiconducting inorganic double helix: New flexible semiconductor for electronics, solar technology and photo catalysis September 15th, 2016

World's most powerful X-ray takes a 'sledgehammer' to molecules September 14th, 2016

Researchers design solids that control heat with spinning superatoms: Carnegie Mellon University and Columbia University collaborators discover the cause of vastly different thermal conductivities in superatomic structural analogues September 8th, 2016

For first time, carbon nanotube transistors outperform silicon September 8th, 2016

Discoveries

Fighting cancer with sticky nanoparticles September 27th, 2016

Gold nanoparticles conjugated quercetin inhibits epithelial-mesenchymal transition, angiogenesis and invasiveness via EGFR/VEGFR-2 mediated pathway in breast cancer September 27th, 2016

UNAM develops successful nano edible coating which increases life food September 27th, 2016

Crystalline Fault Lines Provide Pathway for Solar Cell Current: New tomographic AFM imaging technique reveals that microstructural defects, generally thought to be detrimental, actually improve conductivity in cadmium telluride solar cells September 26th, 2016

Announcements

Leti and Taiwanese Tech Organizations Sponsoring Workshop in Taipei on MEMS, IoT, Smart Lighting Applications, System Reliability & Security September 28th, 2016

Oxford Instruments systems now facilitate water purification technology September 27th, 2016

Dr Barbara Armbruster promoted to Worldwide Sales and Marketing Director for XEI Scientific September 27th, 2016

Fighting cancer with sticky nanoparticles September 27th, 2016

Water

Oxford Instruments systems now facilitate water purification technology September 27th, 2016

Atomic scale pipes available on demand and by design September 9th, 2016

University of Akron researchers find thin layers of water can become ice-like at room temperature: Results could lead to an assortment of anti-friction solutions August 30th, 2016

SLAC, Stanford gadget grabs more solar energy to disinfect water faster: Plopped into water, a tiny device triggers the formation of chemicals that kill microbes in minutes August 15th, 2016

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







Car Brands
Buy website traffic