Materials Physics for Latch-Mediated Spring Actuation (LaMSA)

Nature is masterful at using limited components and basic driving forces to achieve complex tasks across a broad range of size scales. Remarkable examples include organisms, such as mantis shrimp and trap-jaw ants, which use Latch-Mediated Spring Actuation (LaMSA) to achieve high power, impulsive movements. These systems use actuators to store energy in spring elements through latch engagement. Upon release, the springs recoil at high rates, giving rise to impressive predatorial, escape, and dispersal movements. The enabling materials rely upon integrated phases to provide internal transport, energy storage, efficient recovery, protective dissipation, and real-time control. Here, we identify underlying principles of LaMSA systems, focusing on physics that define enabling structures-property relationships. We establish scaling relationships to decouple materials and geometric contributions to LaMSA systems and demonstrate understanding through reduced physical models. From these lessons, we develop materials systems, including metamaterials and polymer gels, with advanced performance capabilities.