Bidirectional Bending Soft Actuator with Multistimuli Responsiveness for Environmental Pollutant Monitoring

Soft actuators have emerged as promising tools for environmental monitoring; however, most existing actuators suffer from multistimuli cross-sensitivity and limited adaptability across various environments. Herein, we propose a bilayer soft actuator composed of a graphene-doped polydimethylsiloxane (G@PDMS) layer and a poly(vinylidene fluoride) (PVDF) layer, capable of effective deformation in both air and aqueous environments while exhibiting selective responsiveness. The actuator demonstrates multistimuli responsiveness to organic solvents/vapors, thermal radiation, and infrared (IR) radiation in air, achieving bidirectional deformation under organic stimuli with a remarkable bending angle of 630° and a load capacity of 180 times its self-weight. In aqueous environments, the actuator exhibits minimal response to thermal and IR light stimuli but shows high selectivity and rapid response to specific organic pollutants, with a response time of just 1.77 s to dichloromethane. Leveraging these properties, we developed a series of functional actuators─including Miura origami, airfoil, and artificial muscle configurations─demonstrating their capability to replicate complex movements. Moreover, a water lily-inspired multienvironmental actuator was designed to effectively shield against underwater temperature fluctuations, IR light, and nontarget organic solvent interference, showing its cross-insensitivity and potential for real-time environmental monitoring applications.