Decoupled and non-volatile prestress programming of tensegrity metamaterials enables persistent mechanical function

Traditional programmable mechanical metamaterials are often fundamentally limited by their dependence on continuous external energy or manual intervention to sustain their tuned states, which constrains their autonomy and real-world viability. Inspired by the defensive behavior of the pufferfish, we introduce a tensegrity design that enables the decoupling of stimulus-triggered programming from fast, passive mechanical responses. We integrate stimulus-responsive hydrogels as programmable drivers with mortise-tenon joints that provide non-volatile mechanical memory, thereby enabling persistent storage of prestress within the material architecture. Once activated by ambient humidity, the prestress state and corresponding mechanical behavior, including bistable or monostable responses, are set, and no energy is needed to maintain the state over long periods. We demonstrate three proof-of-concept configurations—timed release, impact protection, and adaptive load bearing—on a unified tensegrity platform, establishing a “program once, function persistently” strategy for autonomous, energy-conserving smart materials.