National Science Foundation
boosts research of NIU chemist

by Tom Parisi

The National Science Foundation is showing keen interest in the research of NIU chemist Petr Vanýsek and University of Illinois at Chicago physicist Mark Schlossman. The two scientists are breaking new ground in understanding why liquids, such as oil and water, don’t mix.

NSF has awarded $535,000 over three years to the researchers for their continued study of the molecular boundary between immiscible (unmixable) liquids. NIU’s portion of the grant is about $98,000, Vanýsek said.

Gaining a better understanding of why immiscible liquids won’t mix could lead to numerous applications, from improving oil-spill cleanups to providing superior delivery of drugs through the oil-like human cell membranes.

Scientists have known that two immiscible solvents must somehow communicate to each other that they should not mix. But until recently researchers have never known for sure what goes on at the molecular boundary between two immiscible liquids.

Vanýsek and Schlossman led a team of scientists who demonstrated for the first time a seldom-predicted layering phenomenon at the boundary. The findings were published in January 2006 in the journal Science.

The researchers used the Advanced Photon Source at Argonne National Laboratory, the most powerful X-ray facility in the Western Hemisphere, to closely examine the boundary between water and nitrobenzene, an oil-like substance.

“We showed that the molecular boundary is comprised of a layered structure of ions – charged particles at the smallest possible dimension,” said Vanýsek, an NIU electrochemist. “There is some degree of mixing of the two solvents right at the interface.
In addition, the ions near the interface are stacked in a couple of layers rather than just distributing smoothly throughout.”

The new project again will use the Advanced Photon Source for a more in-depth study of the ion distributions and pairings.

8-21-06