Hydrogel Fiber Actuators Prepared by Shell–Core Structure for High-Performance Water/Light Dual Response

Spiral fibers with high energy storage and high output efficiency are highly desirable for soft robots and actuators. However, it is still a great challenge to achieve spiral fibers with excellent water actuation performance, structural stability, and high scalability in a low-cost strategy. A coaxial spiral structure is reported for the fabrication of high-performance fiber actuators. The developed shell–core helical fiber actuators were based on alginate/poly(ethylene glycol) acrylate shell and alginate/GO core with green and excellent spinnability. Owing to the high water-absorbing-swelling capacity and energy storage of the shell, the prepared spiral fibers are characterized by fast response, high energy output, and good repeatability of cycling. On the other hand, the core endows the spiral fibers with the additional features of strong force retention and photothermal response. The shell–core spiral structure promotes the output efficiency of the twisted fiber actuator with a large rotation (2500°/cm), untwisting speed (2250 rpm), and recovery speed (2700 rpm). In addition, the tertiary spiral structure based on TAPG fibers exhibits excellent humidity and photothermal response efficiency. The application of fibers to smart textiles enables efficient human epidermal thermal management.

Graphical Abstract