Pratt Fellow Crabtree Seeks Understanding of Flaws in "Smart Gels"

Liza Crabtree, a Pratt Undergraduate Research Fellow and civil and environmental engineering major, is working to understand the flaws that can develop in so-called stimulus-responsive hydrogels. These ‘smart gels,’ which look essentially like Jello, can be made to undergo dramatic transformation in response to changes in their surroundings, including pH and temperature. Thanks to those unique abilities, hydrogels are now poised to become integral mechanical components and sensors in the increasingly tiny devices of the future.

Liza CrabtreeIndeed, the shape-shifting gels have already been successfully integrated by others into molecular recognition sensor surfaces, optical switches, drug carriers and microfluidic devices, according to John Dolbow, a professor of civil and environmental engineering and one of Crabtree’s research advisors. Yet, there is still a lot about the gels’ complex behaviors and abilities that remains mysterious.

Crabtree is focusing her efforts on understanding one drawback of the gels: Their tendency to develop flaws that can spread. Ultimately, she aims to identify formulas for making the gels that would help resist failure.

To that end, she measures their basic material properties, testing their performance under tension, for example. It’s a task that’s easier said than done.

“It’s complicated because you have to examine them under a microscope and they also need to be in water. It’s required a lot of individual innovation— a lot of trial and error,” Crabtree said. “I knew nothing about materials science in the beginning. I’ve learned a lot on my feet.”

The Path to Duke

Crabtree said she found out about Duke from her mother, who is an alumna. Although she was initially skeptical whether her mother’s alma mater would be right for her, a visit to campus quickly dispelled any doubts. “I visited with a friend and had such a wonderful time,” she said. “I decided almost immediately I wanted to go.”

In her senior year of high school, she had chosen to take two math classes and two physics classes. To follow those interests, she opted to apply to the Pratt School of Engineering.

In addition to her work with Pratt Fellows, Crabtree is also involved with the student chapter of Engineers Without Borders (EWB). She was a member of the team that traveled to Uganda last summer to install a rainwater harvesting system designed to supplement the water supply for a local university.

“It was eye-opening,” she said. “We lived without running water. I was prepared for the bottled water and pit latrines, but I wasn’t prepared for having so few showers. Any household water we used had to be collected and carried from a borehole over a mile away.”

She said she particularly enjoyed learning about Ugandan culture and about the attitudes of Ugandan people towards them as wealthy Americans.

Crabtree is also a member of two choirs, a sorority and the American Society of Civil Engineers.