Fig. 2. GO-PDA/rGO photoactuators and photothermal actuation mechanism.

(A) Schematic representations of the structures and mechanisms of the graphene paper. If there is no NIR light irradiation, the GO-PDA/rGO region flattens. A flat, freestanding GO-PDA/rGO region starts to bend immediately upon exposure to NIR light irradiation. This bending/unbending mechanism is completely reversible over many cycles. (B) Series of optical images showing the light actuation process of the MGM (100 mW cm⁻²) (scale bar, 3 mm). Bending angle as a function of time as light is turned on (period, 8 s) and off (period, 12 s). (C) Dependence of bending angle on illumination intensity (scale bar, 5 mm).