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Nature article puts spotlight on liquid-crystal work by DelVal professor

May 30, 2012

If you are reading this on a computer screen, you may be looking at liquid crystals right now – miniscule bits of matter that have some properties of a solid crystal, but can move in the fluid way of a liquid.

These liquid crystals can be found in everything from flat screen televisions to digital clocks, and recent computational work by Dr. Ed Sambriski, professor of chemistry, may lead the way to discovering even more technological uses for these tiny structures.

Sambriski worked as part of an international team on a study recently published in the journal Nature. The team was led by his former advisor, Juan J. de Pablo, a professor in the Department of Chemical and Biological Engineering at the University of Wisconsin-Madison (UW-Madison), where Sambriski completed his post-doc before joining DelVal.

Other collaborators included former postdoctoral fellows J. A. Moreno-Razo, who is now at the Autonomous Metropolitan University, Iztapalapa Campus (UAMI) in Mexico City; Nicholas L. Abbott, of UW-Madison; and J. P. Hernández-Ortiz of the National University of Colombia, Medellin Campus (UNAL).

The study used computer simulations to examine how liquid crystals interact with other molecules at very small scales.  The resulting models showed how the rod-shaped crystals are expected to behave when particular conditions, such as temperature and concentration, are changed in a laboratory setting.

What the researchers discovered could have big implications for the creation of small things. The simulations showed that when droplets of liquid crystals coated with water and other types of molecules, known as surfactants, are cooled, intricate water-surfactant arrangements can form on the droplet surface.  These arrangements allow droplets to “talk” to each other, enabling them to form structures, such as grids and wires, on their own.

The intricate water-surfactant patterns that emerged on the droplet surface were unexpected, and the finding could lead to the development of new materials and technologies at the molecular scale. 

“It means we could drive chemistry so things can assemble on their own,” Sambriski explained.  “This may allow for the mass production of devices on a nanoscale, an important feat in overcoming the limitations of the ‘mechanical tools’ we have at that scale.”

Such production could be used to create new technologies for a wide range of fields, from health care, to environmental science, to computing. 

Sambriski said now that the study is complete, the next phase of research will focus on more sophisticated models and on experimental work to fine-tune and optimize the self-assembly behavior for actual use.

The continued research could result in many real-world uses of their findings in the manufacture of devices, including environmental and biological sensors, tiny circuits for quantum computers, or even light-controlled switches.

“There is a big drive that doesn’t seem to go away to make things smaller and smaller,” Sambriski said.