Published on July 5th, 2009 | by Tina Casey3
Stretchable Salt Could Unlock Secrets of Smog
It’s “not supposed to do that,” but it is: salt has revealed a previously undiscovered talent for stretching. The startling revelation was made by researchers from Sandia National Laboratories and the University of Pittsburgh, using a powerful Interfacial Force Microscope. The discovery of stretchable properties in salt could lead to the development of more efficient desalination technology, and it could also provide more insight into the potential for alternative fuels to contribute to smog formation.
Salt and Smog
When ocean water evaporates it forms microscopic airborne particles of salt, or aerosols. Salt is sodium chloride, which can interact with other airborne pollutants to form chemicals such as sodium sulfate and sodium nitrate. For example, pollutants blowing over the Pacific Ocean pick up salt-laden air, contributing to the notorious Los Angeles smog. Sea salt aerosols also act as an asthma trigger and may contribute to ozone destruction.
Stretchable Salt and The Interfacial Force Microscope
The discovery of stretchable salt was made possible by a device called an Interfacial Force Microscope, developed by Sandia National Laboratories. The device is used to develop and test microelectromechanical systems. It is capable of measuring the mechanical and adhesive properties of a single layer of organic molecules, using a force feedback sensor that remains rigid and stable. While using an interfacial force microscope to examine a tiny block of sea salt, the researchers observed that the supposedly brittle substance clung to the nanometer-sized tip of the microscope. It created a bubble-like formation, behaving much like the surface of water (place a few drops of water on a flat surface and touch it with your fingertip to observe a similar effect). As the tip was withdrawn, the bubble elongated to form a shape resembling nanowires.
A Better Understanding of Smog
As the world searches for alternative fuel sources, the mixed record of ethanol and other biofuels as truly sustainable fuels clearly indicates the need for a better understanding of the interaction between airborne particles found in nature and those contributed by human activity. Along with new observational tools such as a satellite-based pollution radar, the discovery of the stretchable properties of salt could lead to a more sustainable approach to the development and use of combustible alternative fuels.
Desalination and Stretchable Salt
The researchers also note that the discovery could lead to improvements in cutting edge desalination technology, which strains salty water through nanotube membranes such as those developed by the Lawarence Livermore National Laboratory in California.
Image: Courtesy of Sandia National Laboratories.