The average person spends about on their smartphone a day. In that time spent scrolling, do you ever stop to wonder what materials your phone screen is made of or why it works?
These screens are made from nematic liquid crystals, the most common form of the fourth state of matter that exists between liquid and solid.
Four professors, Antal Jakli, Ph.D., professor of materials science; Robert Tweig, Ph.D., professor of chemistry; and Samuel Sprunt, Ph.D., and James Gleeson, Ph.D., both professors of physics, are among the first to investigate how ferroelectric liquid crystals are affected when electric fields are applied to their field of existence. The team received an $831,000 grant from the National Science Foundation to test its hypotheses.
Liquid crystals were first discovered in 1888 by Freidrich Reinsitzer and Otto Lehmann, and it is estimated that there are around 100 different phases of liquid crystals. One of these phases is , which have been theorized to exist since 1916. However, researchers were unable to actually demonstrate their existence until 2017.
Given how recently ferroelectric liquid crystals were discovered, there is still a wide field of research to be done regarding this one phase of liquid crystals.
“These materials are predicted to be used for supercapacitors,” Jakli said. “Where you can charge them and they store the energy, then you can very quickly use this energy.”
However, the basis of Jakli and his co-principal investigators' research is to understand the electromechanical effect on ferroelectric liquid crystals. To do this, the researchers apply a voltage in audio frequency, anywhere in the range of 20 hertz to 20 kilohertz, to a film of liquid crystals. When applied, this voltage should cause the crystals to vibrate and omit sound at the frequency of the voltage.
“We are trying to find the connection between the electric field and the mechanical exertion,” Jakli said. “They could be used as speakers, which is not our main goal, but there are a lot of connections that people haven’t studied, so we’d like to see how they perform.”
To conduct this research, the investigators are utilizing facilities across Kent State’s campus in the liquid crystals, physics and chemistry departments. Some of the tools and expertise needed for this research include X-ray instruments, light-scattering technique, polarizing microscopes, chemical synthesis and dielectric measurements.
It is predicted that these ferroelectric liquid crystals may eventually be able to power supercapacitors that can store energy and quickly power machines like electric cars. Another predicted use of these crystals is for electro optics and special displays.
“Imagine, you can make your screen also a speaker,” Jakli said. “So someone is speaking on the screen, and then you can hear the song exactly from their mouth.”
The current research being done at Kent State is only one of the first steps in the process of understanding ferroelectric liquid crystals. The goal of this research is to understand more about the function of the liquid crystals, which will hopefully lead to future research on how to implement ferroelectric liquid crystals into technology.
This research also offers opportunities for students in the Department of Physics and the materials science graduate program to gain experience in a lab setting.
“It's very important that the students are involved in this work. That's the best way they learn what they do,” Jakli said. “And at the end they write a dissertation. On average, in materials science, every student has about four published papers before they graduate.”
Jakli said this research is important for him to teach students because it is similar to the research he pursued when obtaining his doctorate in which he conducted electromechanical studies of other ferroelectric materials.
“I did it when I studied for my Ph.D.,” Jakli said. “What you do during your Ph.D., you really feel at home there. You feel that you know that you earned it.”
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