Ultra-fast and multi-responsive anisotropic nanofibrous actuator with remote control

Abstract

The development of high-performance soft actuators capable of integrating multimodal responsiveness, ultrafast actuation, and programmable deformation remains a critical challenge in soft robotics, primarily due to inherent limitations in current hydrogel-based and elastomer-based systems. These conventional actuators often suffer from compromised functionality, slow response kinetics, and complex fabrication processes. Herein, we present an anisotropic nanofibrous actuator platform that overcomes these limitations through the synergistic combination of structurally aligned electrospun nanofibers and multi-stimulus responsive polymer composites. Our design uniquely integrates three independent actuation mechanisms—thermoresponsive poly(N-isopropyl acrylamide-co-4-acryloyl benzophenone) (P(NIPAM-co-ABP)), photothermally active gold nanoparticles, and pH-sensitive poly(diethylaminoethyl methacrylate-co-methyl methacrylate-co-4-acryloyl benzophenone) (P(DEAEMA-co-MMA-co-ABP))—within an oriented nanofibrous architecture. Precise control of fiber alignment through electrospinning techniques enables programmable directional bending responses, while the bilayer configuration facilitates asymmetric deformation through differential swelling behavior. The highly porous nanofibrous network architecture provides rapid mass transport pathways, yielding exceptional actuation speeds (<0.3 s, 360°) that surpass conventional hydrogel-based systems. Furthermore, the actuator still maintains its rapid responsiveness in the air (4 s, 35°). Additionally, the aligned nanofiber morphology contributes to remarkable mechanical robustness, supporting loads up to 178 times its own mass. This work establishes a versatile materials platform that addresses critical challenges in soft robotics by combining multimodal environmental responsiveness, ultrafast actuation kinetics, and programmable deformation control through a scalable fabrication approach. The design principles demonstrated here provide new opportunities for developing advanced soft robotic systems with biomimetic functionality and enhanced performance characteristics.