14 DAY TRIAL // Virginia Tech, Pennsylvania State University, and Drexel University were awarded a potentially $7.5 million Multi-University Research Initiative (MURI) grant by the Army Research Office to develop electromechanical devices and high-performance membranes using ionic liquids.
An ionic liquid is a liquid that contains essentially only ions. Some ionic liquids, such as ethylammonium nitrate, are in a dynamic equilibrium where, at any time, more than 99.99% of the liquid is made up of ionic rather than molecular species. In the broad sense, the term includes all molten salts, for instance, sodium chloride at temperatures higher than 800 degrees Celsius. Today, however, the term "ionic liquid" is commonly used for salts whose melting point is relatively low (below 100 degrees Celsius). In particular, the salts that are liquid at room temperature are called room-temperature ionic liquids, or RTILs.
Due to their non-volatility, effectively eliminating a major pathway for environmental release and contamination, ionic liquids have been considered as having a low impact on the environment and human health, and thus recognized as solvents for green chemistry.
They are also useful in electrically conductive membranes, thermally stable at high temperatures, and do not evaporate at normal conditions. With today's advanced ability to manipulate molecular structure and design unique molecules, ILs' advantages are being explored for emerging applications.
"The Army needs a myriad of electronic devices that take advantage of the potential synergy of these unique properties", said chemistry professor Tim Long. "Our challenge is to synthesize high performance materials with a particular device in mind. Then the device is truly created from the molecular-scale up."
The ionic liquids will be integrated into membranes to create thin films to perform various functions, such as membranes that can transport or filter small molecules. "Applications include fuel cell membranes, where protons are transported across a membrane to create electricity. One advantage over existing fuel cell materials is that the IL will not evaporate, so future membranes will operate at higher temperatures with higher efficiency."
Another application could be stimuli-responsive materials for micro sensors and smart clothes. "The material would breathe and wick moisture away, but quickly close up in response to a chemical or biological threat. Such a suit could be used by the military, by a firefighter, or in an operating room," said Long. "ILs will serve as the building blocks for elastomers, fibers, and rigid plastics for such uses as protective gear and multilayer assemblies."
US Army Research Office is expecting rapid preliminary results and are confident in their choice of some of the best research laboratories in the country.