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

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.