Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Researchers Measure Flow from a Nanoscale Fluid Jet: Jet measures 20 to 150 nanometers in diameter — just a few hundred water molecules across

A research team has recently verified the classical Landau-Squire theory in the world's tiniest submerged jet — in the range of 20 to 150 nanometers.
A research team has recently verified the classical Landau-Squire theory in the world's tiniest submerged jet — in the range of 20 to 150 nanometers.

Abstract:
Fluid jets are all around us: from inkjet printing, to the "Old Faithful" geyser in Yellowstone National Park, to cosmological jets several thousand light years long.

A Northwestern University researcher with collaborators from Cambridge University, Oxford University, and Centro Nacional de Biotecnología have recently verified the classical Landau-Squire theory in the tiniest submerged jet. The diameter of their jets were in the range of 20 to 150 nanometers, which is the length of just a few hundred water molecules lined up in a row.

Researchers Measure Flow from a Nanoscale Fluid Jet: Jet measures 20 to 150 nanometers in diameter — just a few hundred water molecules across

Evanston, IL | Posted on October 28th, 2013

"The flow rate from this nanojet is in the range of tens of pico liters per second," said Sandip Ghosal, associate professor of mechanical engineering and (by courtesy) engineering sciences and applied mathematics at Northwestern's McCormick School of Engineering and Applied Science. "At this rate, if you had started to fill a two-liter soda bottle at the time the first pyramid was being built in Egypt, the bottle would be about half full now."

A paper describing the research, "A Landau-Squire Nanojet," was published October 14 in the journal Nano Letters.

The nanojet is designed around a glass "nano capillary," which the researchers fabricated by heating an ordinary glass capillary — a hollow glass tube — with a laser and gently pulling it until it broke, creating a fine tip. The researchers applied an electric voltage across the capillary, which was submerged in a salt solution to create an electroosmotic flow that then emerged as a jet.

To measure the jet stream, the researchers built a tiny anemometer — a windmill-like device used for measuring wind speed — from a polystyrene bead less than one-fiftieth the width of a human hair. The bead was held in place by an "optical trap," a finely focused laser beam that served as a spindle for the tiny anemometer. When the bead was positioned in front of the jet, it spun around, and a video camera picked up tiny fluctuations of light from a dimple on the bead.

The novel anemometry technique allowed the researchers to map out the vorticity and velocity fields of the nanojet and compare it to those predicted by the classical Landau-Squire solution of the Navier-Stokes equations, the 200-year-old equations that form the bedrock of classical physics. Their observations proved to be in remarkable agreement with the theory.

"The Navier-Stokes equations and everything derived from it are expected to go awry as we approach molecular scales, but no one knows how far down one can push before it breaks," Ghosal said. "We found that it works very nicely down to tens of nanometers."

The researchers also observed a phenomenon they call flow rectification: an asymmetry in the flow rate with respect to voltage reversal. They found that when the voltage is reversed, the capillary sucks in fluid as expected, but at a much lower rate. The capillary thus behaves like a semiconductor diode — an electronic "valve" that allows current flow in only one direction — but with fluid flowing in place of electrons.

The nanojet has a number of potential novel applications. One possible use is as an ultra-low-volume injector for transferring biomolecules into cells or vesicles, a process used in recombinant DNA technologies important in the production of human insulin and disease-resistant crops. Other possibilities include use as a "flow rectifier" in microfluidic logic circuits, the functional equivalent of semiconductor diodes in microelectronics, and also in applications involving nanoscale patterning and micro manipulation.

In addition to Ghosal, other authors include Nadanai Laohakunakorn and Ulrich F. Keyser of the University of Cambridge; Benjamin Gollnick and Fernando Moreno-Herrero of the Centro Nacional de Biotecnología; and Dirk G. A. L. Aarts and Roel P. A. Dullens of the University of Oxford. The research was conducted earlier this year when Ghosal was Leverhulme Trust Visiting Professor at the Cavendish Laboratory of Cambridge University.

####

For more information, please click here

Contacts:
Megan Fellman

847-491-3115

Copyright © Northwestern University

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 Links

Download paper:

Related News Press

News and information

MRI, on a molecular scale: Researchers develop system that could one day peer into the atomic structure of individual molecules April 20th, 2014

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

Nanomedicine

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

High-temperature plasmonics eyed for solar, computer innovation April 17th, 2014

Discoveries

MRI, on a molecular scale: Researchers develop system that could one day peer into the atomic structure of individual molecules April 20th, 2014

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

'Exotic' material is like a switch when super thin April 18th, 2014

Announcements

MRI, on a molecular scale: Researchers develop system that could one day peer into the atomic structure of individual molecules April 20th, 2014

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals

MRI, on a molecular scale: Researchers develop system that could one day peer into the atomic structure of individual molecules April 20th, 2014

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

'Exotic' material is like a switch when super thin April 18th, 2014

Nanobiotechnology

Targeting cancer with a triple threat: MIT chemists design nanoparticles that can deliver three cancer drugs at a time April 15th, 2014

Biologists Develop Nanosensors to Visualize Movements and Distribution of Plant Stress Hormone April 15th, 2014

In latest generation of tiny biosensors, size isn't everything: UCLA researchers overturn conventional wisdom on nanowire-based diagnostic devices April 11th, 2014

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