CAMBRIDGE, MA -- Imagine if you could drink a glass of water just by inserting a solid wire into it and sucking on it as though it were a soda straw. It turns out that if you were tiny enough, that method would work just fine and wouldn't even require the suction to start.
New research carried out at MIT and elsewhere has demonstrated for the first time that when inserted into a pool of liquid, nanowires wires that are only hundreds of nanometers (billionths of a meter) across naturally draw the liquid upward in a thin film that coats the surface of the wire. The finding could have applications in microfluidic devices, biomedical research and inkjet printers.
The phenomenon had been predicted by theorists, but never observed because the process is too small to be seen by optical microscopes; electron microscopes need to operate in a vacuum, which would cause most liquids to evaporate almost instantly. To overcome this, the MIT team used an ionic liquid called DMPI-TFSI, which remains stable even in a powerful vacuum. Though the observations used this specific liquid, the results are believed to apply to most liquids, including water.
The results are published in the journal Nature Nanotechnology by a team of researchers led by Ju Li, an MIT professor of nuclear science and engineering and materials science and engineering, along with researchers at Sandia National Laboratories in New Mexico, the University of Pennsylvania, the University of Pittsburgh, and Zhejiang University in China.
While Li says this research intended to explore the basic science of liquid-solid interactions, it could lead to applications in inkjet printing, or for making a lab on a chip. "We're really looking at fluid flow at an unprecedented small length scale," Li says so unexpected new phenomena could emerge as the research continues.
At molecular scale, Li says, "the liquid tries to cover the solid surface, and it gets sucked up b
|Contact: Sarah McDonnell|
Massachusetts Institute of Technology