Amplification of Photothermally Induced Reversible Actuation in Non-Woven Fabrics Compared to Bulk Films

The burgeoning field of soft robotics has witnessed a surge in interest, driven by the pursuit of creating precise machines with soft actuators capable of surpassing or aiding human manufacturing capabilities. This work explores light-responsive shape memory actuators derived from electrospun fibers, integrating a "push-pull" azo compound into a poly(ε-caprolactone) matrix. Driven by photothermal conversion, the resulting system exhibits reversible actuation under UV light, demonstrating rapid responses and superior performance compared to film counterparts. More specifically, the significant impact of morphology on both the photothermal behavior and the actuation performance is highlighted by comparing non-woven and bulk shape memory material. The temperature variation induced by UV light in the non-woven was notably affected by scattering effects, leading to the formation of temperature gradients throughout the material. Notably, the study establishes a unique stress-responsive range for fibrous actuators, demonstrating that their porous structure contributes to higher actuation magnitudes at lower stresses compared to conventional films. This innovation holds promise for applications in micro-robotics and biomedical fields, showcasing the potential of fibrous actuators in augmenting human-friendly robotics through their lightweight, flexible, and remotely actuated features.