Navigation Links
Simulations help explain fast water transport in nanotubes
Date:9/16/2008

CHAMPAIGN, Ill. 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.

"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.


'/>"/>

Contact: James E. Kloeppel
kloeppel@illinois.edu
217-244-1073
University of Illinois at Urbana-Champaign
Source:Eurekalert

Related biology news :

1. Are existing large-scale simulations of water dynamics wrong?
2. Computer simulations point to key molecular basis of cystic fibrosis
3. Genes newly explained effect on height may change tumor disorder treatment
4. Eating fish may explain very low levels of heart disease in Japan
5. UGA researchers discover mechanism that explains how cancer enzyme winds up on ends of chromosomes
6. Researchers explain nitrogen paradox in forests
7. Mechanism explains link between apolipoprotein E and Alzheimers disease
8. Statistical tool could explain gene study variations
9. Monarch butterflies help explain why parasites harm hosts
10. Genetic breakthrough explains dangerously high blood glucose levels
11. Computers explain why pears may become brown during commercial storage
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/27/2016)... 27, 2016 Research and Markets has announced ... report to their offering. ... to grow at a CAGR of 12.28% during the ... on an in-depth market analysis with inputs from industry experts. The ... coming years. The report also includes a discussion of the key ...
(Date:6/22/2016)... On Monday, the Department of Homeland Security (DHS) issued ... the Biometric Exit Program. The Request for Information (RFI), ... that CBP intends to add biometrics to confirm when ... , in order to deter visa overstays, to ... Logo - http://photos.prnewswire.com/prnh/20160622/382209LOGO ...
(Date:6/16/2016)... , June 16, 2016 ... is expected to reach USD 1.83 billion by ... View Research, Inc. Technological proliferation and increasing demand ... are expected to drive the market growth. ... The development of advanced multimodal techniques ...
Breaking Biology News(10 mins):
(Date:12/6/2016)... ... ... Discovering new clues to natural treatments that could allow our bodies to ... And searching for keys to our immune systems by studying parasite-resistant fish. These are ... Edith and Peter O’Donnell Awards by The Academy of Medicine, Engineering and ...
(Date:12/6/2016)... and SAN DIEGO , Dec. 6, ... appointment of Santosh Kesari , MD, PhD, FANA, ... leverage his experience in neurology and clinical trials to ... cell for treatment of stroke. The AmnioStem product is a ... has previously shown therapeutic activity in animal models of ...
(Date:12/6/2016)... ... December 06, 2016 , ... RoviSys, a leading independent provider ... Ohio, announced the opening of their new office building today. Located at 480 ... home to 200 employees focused on providing sales, engineering, and support services to ...
(Date:12/5/2016)... ... , ... In anticipation of AxioMed’s exclusive cleanroom manufacturing facility ... Jake Lubinski will be traveling to Germany on December 6th. Mr. Lubinski will ... to discuss the benefits of a viscoelastic total disc replacement. , AxioMed received ...
Breaking Biology Technology: