Researchers from the University of Chicago’s Pritzker School of Molecular Engineering have shown for the first time how to engineer the building blocks needed for logic operations using a type of material called a liquid crystal, paving the way for a completely new way to perform calculations.
The results, published on February 23 in Scientists progresslikely won’t become transistors or computers right away, but the technique could pave the way for devices with new capabilities in sensing, computing and robotics.
“We’ve shown that you can create the basic 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, of the Liew family. Professor of Molecular Engineering and Principal Investigator at Argonne National Laboratory, and senior corresponding author of the paper. “This is a really exciting step for the field of active materials.”
The defect details
The research aimed to take a closer look at a type of material called liquid crystal. Molecules in a liquid crystal tend to elongate, and when grouped together they take on a structure that has a certain order, like the straight rows of atoms in a diamond crystal, but instead of being blocked as in a solid, this structure can also move as a liquid does. Scientists are always on the lookout for these kinds of quirks because they can use these unusual properties as the basis for new technologies; liquid crystals, for example, are found in the LCD television you may already have in your home or in the screen of your laptop.
A consequence of this strange molecular ordering is that there are points in all liquid crystals where the ordered regions collide with each other and their orientations don’t quite match, creating what scientists call “topological defects”. . These spots move when the liquid crystal moves.
Scientists are intrigued by these defects, wondering if they could be used to carry information – similar to the functions electrons perform in the circuits of your laptop or phone. But to make tech out of those flaws, you have to be able to guide them where you want them, and controlling their behavior has proven to be very difficult. “Normally, if you look through a microscope at an experiment with an active liquid crystal, you would see complete chaos — defects moving everywhere,” de Pablo said.
But last year, an effort from Pablo’s lab led by Rui Zhang, then a postdoctoral researcher at the Pritzker School of Molecular Engineering, in collaboration with Prof. Margaret Gardel’s lab at UChicago and Prof. Zev Bryant’s lab at Stanford, found a set of techniques to control these topological defects. They showed that if they controlled where they put energy in the liquid crystal by shining light only on specific areas, they could guide defects to move in specific directions.
In a new paper, they went further and determined that it should be theoretically possible to use these techniques to get a liquid crystal to perform computer-like operations.
“These have many of the characteristics of electrons in a circuit – we can move them long distances, amplify them and close or open their transport as in a transistor gate, which means we could use them for relatively sophisticated,” Zhang said. , now an assistant professor at the Hong Kong University of Science and Technology.
Although the calculations suggest these systems could be used for computational purposes, they are more likely to only be useful in applications such as the field of soft robotics, the scientists said. Researchers are interested in soft robots – robots whose bodies are not made of hard metal or plastic, but rather stretchy, soft materials – because their flexibility and softness to the touch mean that they can perform functions that hard-bodied robots cannot. The team can envision creating such robots that can do some of their own “thinking” using active liquid crystals.
They can also imagine using topological defects to transport small amounts of liquid or other materials from place to place inside tiny devices. “For example, maybe one could perform functions inside a synthetic cell,” Zhang said. It’s possible that nature already uses similar mechanisms to transmit information or perform behaviors inside cells, he said.
The research team, which also includes co-author and UChicago postdoctoral researcher Ali Mozaffari, is working with collaborators to conduct experiments to confirm the theoretical findings.
“It’s not often you get to see a new way of doing computing,” de Pablo said.
This work utilized the resources of the University of Chicago Materials Science and Engineering Research Center.