Fig. 1.

Fabrication and programmable structure changes of actuator. a Schematic diagram of precise PPy patterning on a GO film for the fabrication of a programmed GO/PPy actuator; b optical image of precise PPy patterning on a GO film (Scale bar: 100 μm); c working mechanism of GO/PPy bilayer actuator and the structural changes of actuators with regular triangle, square, regular pentagon, regular hexagon, and H-, U-, S-, and T-shape patterns under the stimuli of humidity and IR light; d schematic diagram of a programmable GO/PPy actuator