The More Exercise, the Better—Bone-Inspired Microporous Composites Enhancing Both Load-Bearing and Energy-Dissipation Capabilities Under Cyclic Loading

Similar to the aging process of our body, materials suffer progressive degradation of their properties over time under repetitive loading that limits the performance and the lifetime of parts. This results in significant costs associated with inspection, maintenance, and downtime. Moreover, materials used in various applications, from soft robotics to spacecraft, require specific performance combinations such as stiffness and dissipation. However, improving one aspect of a material’s performance often sacrifices performance in other properties, commonly referred to as performance tradeoffs, limiting the feasibility of creating materials with optimal performance profiles. To address these challenges, we report a liquid-infused microporous composite that dynamically enhances both load-bearing and energy-dissipation capabilities under cyclic loading and shows a reprogrammable self-folding behavior based on the spatial distribution of mechanical loading. For example, the modulus and the energy dissipation of the material increased by 3,600% and 3,000%, respectively, after 12 million loading cycles. To understand the correlation between microstructure, change, and material performance, we utilized a sub-micrometer resolution computed tomography for in-situ characterizations of the material during loading and unloading. This remarkable behavior is achieved in a bone-inspired process by inducing mineralization from an infused liquid electrolyte upon mechanical loading. Furthermore, similar to bone, which changes its bone mineral density distribution based on the applied loading, the material can be (re)programmed to generate various shapes by self-folding based on the spatial distribution of mechanical loading. We anticipate that our findings provide stepping stones toward unprecedented opportunities in multiple fields, including soft robotics, vehicles, infrastructure, and tissue engineering/medical devices, and can contribute to changing the paradigm of material selection with improved resilience and sustainability.