Scalable Wet-Spinning Approach to Fabricate Polydimethylsiloxane Composite Fibers for Tunable Photomechanical Actuators

Photomechanical actuator with large deformation and rapid response is highly desirable for smart textiles and soft robots. However, the conventional polydimethylsiloxane (PDMS) elastomer-based actuators with multilayered or blocky configuration suffer from interlayer instability, low effective utilization area, and manual assembly processes, which limit their practical application. Herein, a series of PDMS composite fibers were fabricate through a scalable wet-spinning approach. To investigate the effects of light-responsive material dimension on the photomechanical performance of PDMS composite fibers, pseudo-1D gold nanorod (AuNR), 1D carbon nanotube (CNT), and 2D reduced graphene oxide (RGO) were used as photoresponsivity materials. To obtain a superior photomechanical property of these fibers, the effects of the light intensity, pre-train, fiber diameter, filler concentration and chemical structure were discussed, and their light-induced actuation mechanisms were presented. Among them, the RGO/PDMS fiber actuator showed the highest actuation stress (72.1 kPa at 40% pre-stain), while the AuNR/PDMS fiber actuator exhibited the fastest response times of 12.6s at 40% pre-strain. This study provides valuable insights for the design and development of fiber actuators with outstanding photomechanical performance.