Sequential Ion Induced Multilength‐Scale Structurally Fibers with Strain‐Stiffening, High Damping, and Shape‐Memory Features

Abstract Natural materials possess inherent multilength‐scale structures, showcasing outstanding mechanical properties such as strain‐stiffening, high damping, and shape‐memory features under ambient conditions. Such integrated properties are highly desirable for advanced materials in biomedical devices and soft robots but remain challenging in synthetic materials. Herein, a novel strategy of sequential ion treatment is employed to introduce micro/nanoscale‐ordered structures and molecular‐scale stimulus responses into hydrogel‐derived self‐assembly fibers under ambient conditions. The treated fibers exhibit strain‐stiffening properties with a high toughness of 257 MJ m −3 and 73% damping capacity comparable to spider silk. Owing to their cross‐linking network and reversible secondary structure, those fibers exhibit outstanding water‐stability, wet stretchability, and hydration‐responsive shape‐memory performance, with ultimate elongation of 407%, shape‐fixity ratio of 94%, and shape‐recovery rate of 97%. This work furthers the green fabrication of smart materials with multifunction and presents promising applications in diverse fields, including biomimetics and biomedicine.