Researchers Discover New Way of Computing With Liquid Crystal

Researchers at the University of Chicago Pritzker School of Molecular Engineering have demonstrated how to design the basic elements needed for logic operations with a material called liquid crystal. The new development is the first of its kind, and it could lead to a brand new way of performing computations. 

The research was published in Science Advances.

While the new technique will not result in transistors or computers right away, it could go a long way in creating devices with new functions in computing, sensing, and robotics.

Juan de Pablo is a Liew Family Professor in Molecular Engineering and senior scientist at Argonne National Laboratory. He is also senior author of the research. 

“We showed you can create the elementary building blocks of a circuit — gates, amplifiers, and conductors — which means you should be able to assemble them into arrangements capable of performing more complex operations,” said Juan de Pablo. “It’s a really exciting step for the field of active materials.”

Liquid Crystals

The research heavily focused on a type of material called a liquid crystal. One of the unique properties of a liquid crystal is that its molecules are usually elongated, and they adopt a somewhat ordered structure when they are packed together. However, this structure can shift around similar to liquid, and scientists can use unique properties like this to build new technologies. 

The different molecular order means that there are spots in all liquid crystals where the ordered regions can come into contact with each other. Since their orientations don’t match perfectly, scientists call it “topological defects,” and the spots move around as the liquid crystal also moves. 

The team of scientists is exploring whether these defects could be used to carry information. With that said, creating technology out of them would require the ability to move them around where wanted, and it has been extremely difficult to control their behavior up until this point.

“Normally, if you look through a microscope at an experiment with an active liquid crystal, you would see complete chaos — defects shifting around all over the place,” said Juan.

The Breakthrough

The breakthrough came last year with a project in Pablo’s lab headed by Rui Zhang, who was a postdoctoral scholar at the Pritzker School of Molecular Engineering. He worked alongside Prof. Margaret Gardel’s lab from UChicago and Prof. Zev Bryant’s lab from Stanford. 

The team discovered a set of techniques that could be used to control the topological defects. If they controlled where they put energy into the liquid crystal, which was done by shining light on specific areas, the defects could be guided in specific directions. 

“These have many of the characteristics of electrons in a circuit — we can move them long distances, amplify them, and shut or open their transport as in a transistor gate, which means we could use them for relatively sophisticated operations,” said Zhang.

While calculations suggest that the systems could be used for computations, they would most likely be more useful in the field of soft robotics. The team believes they could create soft robotics that carry out some of their own “thinking” with the help of active liquid crystals. 

They also hope that the topological defects could be used to transport small amounts of liquid or other materials inside tiny devices. 

“For example, perhaps one could perform functions inside a synthetic cell,” said Zhang. 

The research team also includes co-author and UChicago postdoctoral researcher Ali Mozaffari. The team will now work to carry out experiments to confirm theoretical findings.