Graphene Oxide/Nanofiber-Based Actuation Films with Moisture and Photothermal Stimulation Response for Remote...

The rapid development of intelligent technology and industry has induced higher requirements for multifunctional materials, especially intelligent materials with stimulus-responsive self-actuation behavior. In this study, a Cu@PVA-co-PE/GO composite actuation film, with an asymmetric sandwich structure, was prepared by attaching graphene oxide (GO) to the surface of a polyvinyl alcohol ethylene copolymer (PVA-co-PE) nanofiber composite film containing copper nanoparticles (Cu) through layer-on-layer adsorption. This unique structural design endowed the composite film with not only excellent structural stability but also different bending directions (in response to moisture and infrared light). The actuation performance shows that when the adsorption time was 4 h, the maximum bending angle of the Cu@PVA-co-PE/GO composite film was up to 90° within 5.99 s. Furthermore, the actuation behavior was stable after 100 cycles of reversible moisture stimulation. Additionally, the maximum actuation strain of the composite film was up to 1.35 MPa during the illumination time of 6.8 s and maintained an excellent stability for 400 s under continuous infrared stimulation of 0.53 W/cm². The rapid and sensitive stimulus response of the Cu@PVA-co-PE/GO composite film exhibited self-actuation behavior under the remote control of moisture and infrared light. This, in turn, suggests prospects for wide applications in emerging technologies, such as intelligent switches, artificial muscles, intelligent medical treatment, and flexible robots.