Cars inch forward slowly in traffic jams, but molecules, when jammed up, can move extremely fast.
New research by Northwestern University researchers finds that water molecules traveling through tiny carbon nanotube pipes do not flow continuously but rather intermittently, like stop-and-go traffic, with unexpected results.
“Previous molecular dynamics simulations suggested that water molecules coursing through carbon nanotubes are evenly spaced and move in lockstep with one another,” said Seth Lichter, professor of mechanical engineering at Northwestern’s McCormick School of Engineering and Applied Science. “But our model shows that they actually move intermittently, enabling surprisingly high flow rates of 10 billion molecules per second or more.”
The research is described in an Editor’s Choice paper, “Solitons Transport Water through Narrow Carbon Nanotubes,” published January 27 in the journal Physical Review Letters.
The findings could resolve a quandary that has baffled fluid dynamics experts for years. In 2005, researchers — working under the assumption that water molecules move through channels in a constant stream — made a surprising discovery: water in carbon nanotubes traveled 10,000 times faster than predicted.
The phenomenon was attributed to a supposed smoothness of the carbon nanotubes’ surface, but further investigation uncovered the counterintuitive role of their inherently rough interior.
Lichter and post-doctoral researcher Thomas Sisan performed new simulations with greater time resolution, revealing localized variations in the distribution of water along the nanotube. The variations occur where the water molecules do not line up perfectly with the spacing between carbon atoms — creating regions in which the water molecules are unstable and so propagate exceedingly easily and rapidly through the nanotube.
Nanochannels are found in all of our cells, where they regulate fluid flow across cell membranes. They also have promising industrial applications for desalinating water. Using the newly discovered fluid dynamics principles could enable other applications such as chemical separations, carbon nanotube-powered batteries, and the fabrication of quantum dots, nanocrystals with potential applications in electronics.
Megan Fellman | EurekAlert!
Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst
Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
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In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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