Students: Abby Devlin, Jimmy Hastie

Project: Use of CO2 to Trigger Reversible Volume Phase Transition in Hydrogels

Poster: Vertical (PDF) | Horizontal (PDF)

Institution: Lafayette College

Major: Civil Engineering

Advisor: Melissa Gordon


Smart materials are often inspired by natural processes that are responsive to environmental stimuli. CO2 has garnered interest as a stimulus as it is abundant, inexpensive, and non-toxic. Swelling, or the process of absorbing water, is a fundamental property of hydrogels yet is often not controlled using an environmental stimulus. In this work, CO2 is used to trigger pronounced, reversible swelling of a crosslinked hydrogel. Specifically, CO2 responsivity was conferred to hydrogels with a volume phase transition temperature (VPTT), which demarcates the transition from a collapsed to swollen state. We show that these gels display a CO2-switchable volume phase transition that enables gas-triggered swelling at a constant temperature. To tune the VPTT, compositional studies were conducted to evaluate the effect of varying co-monomer content on the resulting VPTT shifts in these samples. Increasing the concentration of the CO2-responsive moiety resulted in an increase in the initial VPTT as well as a greater shift in the VPTT after CO2 exposure. Isothermal swelling studies conducted at a temperature between the VPTTs before and after CO2 exposure show that CO2 triggers a reversible volume transition and controls swelling. The results presented here demonstrate the promise of CO2 as a stimulus for the design and study of smart materials, which may find applications in drug delivery, microfluidics, and soft actuators.

Abby Devlin

About Abby Devlin

Abigail Devlin, a senior Chemical Engineering major at Lafayette College from San Diego, California. She conducts research under the guidance of Professor Melissa Gordon on novel CO2 responsive hydrogels to determine their physical properties. Outside of research, Abby is on the Division 1 volleyball team at Lafayette. She also participates in Engineers without Borders, AIChE, and intramural clubs on campus.

Jimmy Hastie

About Jimmy Hastie

James Hastie, a senior Chemical Engineering major at Lafayette College from Cheshire, Connecticut. He conducts research under the guidance of Professor Melissa Gordon on characterization of the physical properties of novel stimuli responsive hydrogels. He is currently working towards the completion of his honors thesis. Outside of his research Jimmy is a member of the Rho chapter of the Chi Phi Fraternity as well as the Lafayette chapter of Tau Beta Pi.