Bioinspired Electrically Activated Soft Bistable Actuators

Abstract

AbstractMovement and morphing in biological systems provide insights into the materials and mechanisms that may enable the development of advanced engineering structures. The nastic motion of plants in response to environmental stimuli, e.g., the rapid closure of the Venus flytrap's leaves, utilizes snap‐through instabilities originating from anisotropic deformation of plant tissues. In contrast, ballistic tongue projection of chameleon is attributed to direct mechanical energy transformation by stretching elastic tissues in advance of rapid projection to achieve higher speed and power output. Here, a bioinspired trilayered bistable all‐polymer laminate containing dielectric elastomers (DEs) is reported, which double as both structural and active materials. It is demonstrated that the prestress and laminating strategy induces tunable bistability, while the electromechanical response of the DE film enables reversible shape transition and morphing. Electrical actuation of bistable structures obviates the need for continuous application of electric field to sustain their transformed state. The experimental results are qualitatively consistent with our theoretical analyses of prestrain‐dependent shape and bistability.