Friday, November 21, 2025
UNT's Xiao Li, College of Engineering's Assistant Professor of Materials Science and Engineering with Giordano Tierra, Department of Mathematics Associate Professor
Thanks to an interdisciplinary partnership and an unlikely muse, researchers at the University of North Texas have prototyped a new material that could be used for next-gen wearable devices.
Xiao Li, Assistant Professor of Materials Science and Engineering led the project, which was funded by her National Science Foundation Faculty Early Career Development Program award she received in 2024.
“As wearable electronics, soft robotics and foldable displays continue to advance, the demand for stronger materials has never been greater,” Li says. “Using a Bouligand-inspired architecture, our material combines mechanical toughness with programmable optical properties.”
A Bouligand structure is made of many thin layers that are stacked on top of each other, with each layer slightly rotated to form a compact helix. Li got the inspiration for using this structure from the ocean. It’s commonly found in seashells, mantis shrimp claws and coelacanth scales.
“When sudden force hits the surface, the twisted structure can dissipate the energy to prevent cracking,” Li says. “The challenge is how to consistently create that structure in a membrane that is only between three to 12 micrometers thick.”
Li and her team of students used liquid crystals to form the membrane. Liquid crystals are a state of matter between liquid and solid and are commonly used in liquid-crystal display (LCD) screens.
While liquid crystals naturally form helices, Li’s goal was to have the crystals twist again to create a material made of a helix within a helix. To guide the liquid crystals into the proper shape, her students traveled to Argonne National Laboratory in Illinois for assistance with creating a chemical pattern to guide the self-assembly of chiral liquid crystals.
“They were very excited to go, and it was a good experience for them to work with the specialized equipment there.”
Back at UNT, Li’s group collaborated with Associate Professor Giordano Tierra in the mathematics department. Tierra and his graduate student ran simulations of the material’s formation.
“What we do is try to understand what is happening in the experiment,” Tierra says. “There’s a lot of discussion involved because the engineers will see something they don’t fully understand, and it’s our job to provide additional insights with these simulations.”
Li and Tierra have been working together on similar projects for nearly six years. They first met when they both started at the university.
“We met during one of the mixers between the College of Science and College of Engineering,” Tierra says. “Those are so important for people to go to because we found out that we were doing similar work in our labs, decided to team up and have written four papers together now.”
Tierra says interdisciplinary collaborations like theirs also benefit the students.
“It’s especially good for math students because they don’t get to be exposed to real life applications often. It also challenges students from both disciplines to learn how to communicate with one another and understand what each side is doing.”
Over the past year, through many experiments and simulations, the team was able to reliably develop the thin material. Tierra says he and his student even created a new algorithm for their simulations.
“This is a new topic that the math community has begun to look at only in recent years because it’s very complicated. We think our algorithms will be very helpful to future research, especially because they don’t need a supercomputer to run. It’s very efficient.”
After testing and refinement, the team created a mechanically stable and strong membrane
material. They found that the helix kept its form when stretched and that it would
change color when exposed to an electric field.
“This means we could adapt this to change colors when exposed to different temperatures, like turning red if the material becomes too hot,” Li says.
Since the material is still a proof-of-concept prototype, the next step will be to perform real-time studies to capture the material’s formation evolution as it happens from start to perfect double helix structure. Li also plans to collaborate with biomedical engineering professor Yong Yang and look into ways the material can be adapted for wearable medical devices.
As for Tierra, whose work usually focuses on complex fluids, such mixtures made of liquids with different components, he says he and Li are already in the planning phases of their next project. He hopes more students will join them since interdisciplinary training provides useful skills to gets jobs in either academia or industry.
“We are always looking for students who are interested in research,” Tierra says. “It may be challenging, especially in mathematics, but when you see the final result and solve that challenge, it’s very fulfilling.”
From UNT News – Research by Amanda Lyons