$1 million Army grant aimed at adaptive fluid materials

David Kubarek
January 09, 2019

UNIVERSITY PARK, Pa. — Lauren Zarzar, assistant professor of chemistry at Penn State, has been awarded a five-year, $1 million grant from the U.S. Army to conduct research related to reconfigurable fluids.

Zarzar was awarded an Early Career Awards for Scientists and Engineers grant, which is given by the Army to the nation’s top young investigators.

Zarzar’s research focuses on how complex fluids — such as droplets of two or more encapsulated oils — can be manipulated. Understanding how these fluids can be controlled and rearranged could pave the way for many new technologies such as dynamic materials, tunable optical lenses, sensors and displays.

“If you understand how to make the shape and interfaces of liquids respond to a chemical stimulus you could use it for all sorts of things,” Zarzar said. “You could create adaptive camouflaging materials that dynamically change color. You could use it for the controlled release of a chemical or the encapsulation of another.”

Zarzar’s group will explore ways of reshaping complex fluids in response to stimuli. We know that surface energy is what causes droplets to take certain shapes, said Zarzar, for example, one liquid could surround another because it takes the least energy. But we don’t have good a good understanding of how to manipulate fluids to use them as materials with controllable shapes, or how to control reaction networks in complex fluids.

Nature, on the other hand, is filled with countless examples of phase separated liquids that help to control chemical pathways.

“Organisms are particularly adaptive,” Zarzar said. “One aspect that enables them to be so adaptive and dynamic is that they’re largely fluid on a cellular level, but maintain organization. Chemicals are constantly being transported across interfaces. We have these very complex reaction networks in nature yet we don’t know how to design those sorts of interactions into artificial materials.”

Zarzar, who first reported the ability for rearranging complex materials in Nature, hopes to expand her research by delving into how we can control these changes and use them for a desired purpose. Zarzar showed that an oil within another oil could be manipulated to form a Janus droplet — a side-by-side mirror split of each oil — before the droplet was reversed to allow the interior oil to encapsulate the exterior oil.

At a basic level where a complex mixture of oils is surrounded by water, Zarzar’s goal is to understand how to program a feedback loop pattern into the materials. She wants to apply stimulation to the surrounding water, which triggers the shape of the oil droplet to change, and that shape change in turn creates another chemical signal that can feed back into the fluid structure. Different droplets may trigger different chemical signals or respond in different ways.

“Imagine you have this one droplet that’s communicating with the water but now you have thousands of them and they’re patterned at different spots on the surface,” Zarzar said. “Now they can communicate with one another. You have this more complex network of reactions that can turn itself on and off. It could regulate the surrounding environment or tell us something about that environment.”

Zarzar wants to understand how simple spatially controlled reactions in these multiphase droplets can scale to create much more complex systems with adaptive and responsive behavior.

  • droplets containing a hydrocarbon and fluorocarbon phase are dispersed in water in the shape of a Janus emulsion, where each oil is in contact with the water.

    In this image taken with an optical microscope, droplets containing a hydrocarbon and fluorocarbon phase are dispersed in water in the shape of a Janus emulsion, where each oil is in contact with the water. 

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    IMAGE: Penn State

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Last Updated January 09, 2019