Repeatable Power Amplified Actuation of Confined Polymer Gels

Many organisms have evolved the ability to rapidly release potential energy as a tool for survival using Latch Mediated Spring Actuation (LaMSA). In these systems, latches mediate the transition from stable to unstable energy release and play a critical role in integrating the actuator and spring capabilities. One type of latch that is used in natural systems is the snap-through elastic instabilities. Recent work has demonstrated that synthetic gels, swollen with volatile solvents, can be engineered to undergo multiple snap-through events, providing a pathway for energy-efficient, autonomous, high-power movements. However, an energy relationship between snapping, diffusion, and buckling has yet to be defined; this interaction is driven by the interplay between the solvent-infused gel and the surrounding environment. Our approach utilizes the snapping physics of ribbon-shaped gels to predict the number of snaps and to quantitatively describe how geometry, material properties, and mass transport influence snapping behavior. Initial results from this current work have identified relationships between lateral confinement, ribbon modulus, and snapping kinetics that describe trends and limitations of an energy model. Expanding the understanding of this autonomous system will elucidate power amplification using an environmental driving force.