Title:

Non-equilibrium stimuli-responsive soft materials

Speaker:

Prof. Lihua Jin

Affiliation:

University of California, Los Angeles

When:

Tuesday, May 20, 2025 at 11:00:00 AM   Add to Calendar

Where:

MRDC Building, Room 4211

Host:

Yuhang Hu
yhu462@gatech.edu

Abstract

One recent impetus of developing stimuli-responsive soft materials (SRSMs) is to use them for sensors, actuators and soft robots. In these applications, mechanics and multi-physics fields are intrinsically coupled through non-equilibrium thermodynamic processes, including diffusion, reaction, viscoelastic relaxation, etc. The non-equilibrium processes of SRSMs not only determine their response speeds, but also govern how SRSMs spatiotemporally evolve their properties and structures. In this talk, using hydrogels, shape memory polymers, humidity-responsive polymers and liquid crystal elastomers as model SRSMs, I will present a few of our recent studies on programing the spatiotemporal properties, shapes, and locomotion of SRSMs through non-equilibrium processes. First, I will describe how mechanical stress can be used to induce and tune the phase separation processes of hydrogels. Second, I will show that the fracture properties and behavior of SRSMs are also highly intertwined with their non-equilibrium processes. Finally, by utilizing the displacement of SRSMs to alter their interaction with external stimuli, we are able to achieve complex and autonomous motion of SRSMs.

Biography

Lihua Jin is an associate professor in the Department of Mechanical and Aerospace Engineering at the University of California, Los Angeles (UCLA). Before joining UCLA in 2016, she was a postdoctoral scholar at Stanford University. In 2014, she obtained her PhD degree in Engineering Sciences from Harvard University. Prior to that, she earned her Bachelor’s and Master’s degrees from Fudan University. Lihua conducts research on mechanics of soft materials, stimuli-responsive materials, instability and fracture, soft robotics, and biomechanics. She was the winner of the Haythornthwaite Research Initiative Grant, Extreme Mechanics Letters Young Investigator Award, Hellman Fellowship, NSF CAREER Award, ACS PMSE Early Investigator Award, Sia Nemat-Nasser Early Career Award, and SES Huajian Gao Young Investigator Medal.