Continuous dual-network alginate hydrogel fibers with superior mechanical and electrical performance for flexible multi-functional sensors

Hydrogel fibers play a crucial role in the design and manufacturing of flexible electronic devices. However, continuous production of hydrogel fibers with high strength, toughness, and conductivity remains a significant challenge. In this study, ion-conductive sodium alginate/polyvinyl alcohol composite hydrogel fibers with an interlocked dual network structure were prepared through continuous wet spinning based on the pH-responsive dynamic borate ester bonds. Owing to the interlocked dual network structure, the resulting hydrogel fibers integrated superior performance of strength (4.31 MPa), elongation-at-break (>1500 %), ion conductivity (17.98 S m−1) and response sensitivity to strain (GF = 3.051). Benefiting from the excellent performance, the composite hydrogel fiber could be applied as motion-detecting sensors, including high-frequency, high-speed reciprocating mechanical motion, and human motion. Furthermore, the superior compatibility for human-computer interaction of the hydrogel fiber was also demonstrated, which a manipulator could be controlled to perform different actions, by a smart glove equipped with the hydrogel fiber sensors.