"Soft Materials for Soft Machines"
Abstract: Soft machines are transforming the fields of robotics and biomedical devices in that they are capable of sustaining large deformation and interacting safely with fragile objects and human beings. There are many remaining challenges in the field of soft materials and soft machines, including controlling the spatiotemporal reconfiguration of soft materials, fabricating soft materials with superior mechanical properties, and designing soft machines for programmable functionalities. In this seminar, I will talk about our recent progress in addressing these challenges. One important class of building blocks of soft machines are stimuli-responsive soft materials (SRSMs), which can change their shapes or volumes in response to external stimuli. I will first describe our efforts in controlling the spatiotemporal reconfiguration of SRSMs. Using hydrogels, shape memory polymers, and humidity-responsive polymers as model SRSMs, I will demonstrate how to predict their spatiotemporal responses by developing non-equilibrium multiphysics theories, and program their spatiotemporal reconfiguration and autonomous motion by utilizing the interplay between SRSMs and external stimuli. Next, I will talk about the unique fracture behavior of liquid crystal elastomers, which are special SRSMs combining liquid crystals and elastomers. However, tuning the properties of SRSMs through sophisticated chemical synthesis is often challenging. To overcome this limitation, I will demonstrate how we are able to vary the responses of soft materials by manufacturing them into architected materials. Our efforts in designing energy-absorbing architected materials will be discussed.
Bio: Lihua Jin is an assistant 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. Jin’s group conducts research on mechanics of soft materials, stimuli-responsive materials, instability and fracture, soft robotics, and biomechanics. Lihua was the winner of Haythornthwaite Research Initiative Grant from ASME, Extreme Mechanics Letters Young Investigator Award, Hellman Fellowship, UCLA Faculty Career Development Award, NSF CAREER Award and ACS PMSE Early Investigator Award.