Liquid Crystals Captivate and Compel
Oleg Lavrentovich is known internationally for his research in the physics of liquid crystals. A Trustees Research Professor at Kent State, editor of the journal Liquid crystals Reviews, and the principal investigator on a long series of major grant-funded projects, he often communicates in the specialized, technical terms of his scientific subject.
Yet his delight in studying liquid crystals is simple and spontaneous.
“Once you observe these things under a microscope, you’re addicted,” he said. “It’s hard to leave the lab – I don’t want to miss all these beautiful things.”
As he spoke, he projected images of liquid crystals onto a wall-mounted, flat-panel Sony television in his office. The Sony display itself was built on liquid crystal technology that had its roots at Kent State’s Liquid Crystal Institute (LCI). As compelling as the images of liquid crystals are, so is what he has learned about them. Lavrentovich is discovering what else these beautiful materials can do.
For one, liquid crystal-like structures can be used to cloak objects, hiding what should be in plain sight. In experiments, his research group demonstrated the cloaking of a metal wire electrode.
“The electrode does not disappear, just the image of the electrode that we would see disappears,” he explained. “The light goes around an object and reconstructs itself in such a way that the viewer never realizes that there is anything between point A and B.” It’s a way of “manipulating the trajectory of light,” he said.
In a recent paper published in Physics Review Letters, his research group proposed a solution to the relative slowness of liquid crystals in switching back to their natural state after an electric voltage is applied. Their solution was to use crystals that do not need to be rotated to control the way light is allowed to pass through them.
Since these types of liquid crystals switch rapidly, they potentially can be used as light shutters in cameras and as control elements in redirecting control laser beams in satellite communications. Lavrentovich and his group will use an Ohio Third Frontier grant awarded last summer to explore the feasibility of applying their “fast-switching” research in commercial products.
He is also looking at ways to use liquid crystals as a medium for transporting particles -- for example, putting bacteria in a liquid crystal and controlling their movement in a certain direction. This requires looking at how bacteria swim – their mechanics of propulsion in different media – and how they move in a liquid crystal.
And in a recent journal article, a research group led by Lavrentovich observed for the first time the structure of a new type of liquid crystal – one that twists and bends and might enable new technologies, such as biological sensors.
He traces his love of science back to his childhood in Kyiv (formerly Kiev), Ukraine. His mother was a schoolteacher, and his father became a university professor. Their interests were in chemistry and biology. He learned early from his family that “knowledge brings some importance to life and meaning,” he said.
Science was also highly regarded in Ukrainian society. The launch of the first manmade satellite, Sputnik, by the U.S.S.R. in 1957; the magazines for children that were full of science stories and the academic competition in school among peers all encouraged a bent toward science.
“Science was in my environment when I was a little kid,” he recalled.
He earned his bachelor’s and master’s degrees in physics from Kyiv State University and his Ph.D. in physics and mathematics from the Ukrainian Academy of Sciences. He began pursuing an interest in polymers and organic chemistry, and when he later had the opportunity to study liquid crystals, he was hooked.
After travel restrictions eased up in the former Soviet Union in the 1990s, he held visiting appointments at universities in France. When he came to interview for a position at Kent State, it was his first trip to the U.S. He became a senior research fellow at the LCI in 1992.
He is known for research collaborations, assembling teams of researchers with diverse expertise to study multi-faceted problems. In one recent effort, he led a team of 26 researchers from ten institutions.
The graduate students now on his research team come from all over the world, and his research collaborations include ties with scientists at Argonne National Laboratory, the University of Wisconsin-Madison, and his former Institute of Physics in Kyiv. Collaboration is often born of necessity; in his transport project, he needed collaborators who had expertise with bacteria.
Although liquid crystals research has been applied to the everyday products of modern life – cell phones, televisions, and e-readers to name a few – the physics behind these applications became known as early as the 1920s, Lavrentovich said. What he discovers today may be used in the future, but it is the discovery itself that intrigues him.
“Scientists are typically way ahead of applications,” he said.