Mechanically robust hydrogel fibers have demonstrated great potential in energy dissipation and shock-absorbing applications. However, developing such materials that are recyclable, energy-efficient, and environmentally friendly remains an enormous challenge. Herein, inspired by spider silk, a continuous and scalable method is introduced for spinning a polyacrylamide hydrogel microfiber with a hierarchical sheath-core structure under ambient conditions. Applying pre-stretch and twist in the as-spun hydrogel microfibers results in a tensile strength of 525 MPa, a toughness of 385 MJ m-3, and a damping capacity of 99%, which is attributed to the reinforcement of hydrogen-bond nanoclusters within the microfiber matrix. Moreover, it maintains both structural and mechanical stability for several days, and can be directly dissolved in water, providing a sustainable spinning dope for re-spinning into new microfibers. This work provides a new strategy for the spinning of robust and recyclable hydrogel-based fibrous materials.

In this work, inspired by spider silk, a mechanically robust and green recyclable hydrogel microfiber with sheath-core structure and hydrogen-bond nanoclusters is presented, which maintains both structural and mechanical stability for several days. The enhanced mechanical properties can be obtained by applying the pre-stretch and twist in microfibers, which is comparable to spider silk.