“You take a flat sheet of liquid crystal elastomers, heat it and change it into the shape you want. You can think of it like modeling clay but much more sophisticated.”
LCE’s, as they are known, are stimuli-responsive networks of polymers that combine the elasticity of elastomers with the self-organization of liquid crystals. Morgan Barnes, a second-year graduate student in materials science and nanoengineering at Rice University, foresees a time when they might be used in the manufacture of biomedical devices.
“Imagine a touch screen. When you touch it with your finger, a button pops out of the flat screen. At the molecular level, a complex change in shape takes place,” said Barnes, who works in the lab of Rafael Verduzco
, associate professor of chemical and biomolecular engineering (ChBE).
“Morgan is only a second-year grad student but already she is independent and innovative,” Verduzco said. “She’s an outstanding presenter, and won a prize as part of the Smalley-Curl Institute meeting last year, when she was in her first year. She has also mentored a high school student and an undergrad.”
The working title of Barnes’ doctoral thesis is “3-Dimensional Shape Responsive Behavior in Liquid Crystal Elastomers.” Verduzco’s lab has been able to create surfaces with controlled “wrinkling,” a bunching in the texture of the surface caused by a controlled increase in temperature. The surface wrinkling is reversible.
Among the difficulties to overcome is the transition temperature of LCEs, which is higher than room temperature. Other challenges to researchers hoping to harness the potential of shape-responsive LCEs is the slowness of shape change and the unresponsiveness of LCEs to electric and magnetic fields.
“The novelty of Morgan’s work is showing how she can make the materials transform into arbitrarily complex shapes, from things like twisting and bending to different letters engraved on a surface to even the texture of a face on an elastomer,” Verduzco said.
More recently, Barnes has started work on another project: 2-D Kevlar. This material is similar to the well-known polymer Kevlar used in making bullet-proof vests. Instead of making a one-dimensional linear polymer, Barnes is making a 2-D polymer sheet. Her working hypothesis is that the 2-D sheets will have even greater strength than linear Kevlar.
“Rafael gives us tons of feedback on our research. He’s more hands-on than many professors,” she said.
Barnes was born and raised in Austin, where her father and mother owned a printing company. “I’m a little different from some engineering students. I always liked math and science but I never had any STEM-centered hobbies as a child. I was torn between business and engineering,” she said.
Barnes earned a B.S. in mechanical engineering from Baylor University in 2013, and a master’s degree in mechanical engineering and materials science from Duke University in 2015. That same year she married Will Barnes, now a fifth-year graduate student in physics at Rice. Even when she arrived at Rice the following year, Barnes remained uncertain about her major. Her academic direction became focused when she joined Verduzco’s lab.
“There’s a lot of promise in this research area. LCEs might be used on the surfaces of aircraft. We might be able to culture cells on biocompatible LCEs. Given all of that, my goal is to enter academia, to continue my research and to teach,” Barnes said.