Figure 5.

Various stimuli-responsive actuators based on 2D materials. A. B. An actuator based on homogeneous GO film driven by moisture gradient, relying on the in situ formation of a bilayer structure induced by water adsorption, displays flipping locomotion on a moist substrate at 40 °C. Adapted with permission from⁹³. Copyright 2018 Royal Society of Chemistry. C. An IR-transformable architecture assembled from precut r-GO/GO strips that performs reversible transformations between pre-determined poses upon ON/OFF switching of the IR lights. Adapted with permission from⁹⁴. Copyright 2018 John Wiley & Sons. D. Electromechanical actuator based on stacked 1T MoS₂ film shows substantial curvature changes induced by charge intercalation (E. and F.), leading to the fabrication of inverted-series connected bimorph actuator (G. and H.). Adapted with permission from⁹⁵. Copyright 2017 Springer Nature. I. Magnetically responsive behaviors of multilayered 2D materials intercalated with paramagnetic holmium ions. J. Magnetized Ho³⁺-GO wheel can be actuated remotely by a magnet to perform designed actions, including rolling right, clockwise rotating, and rolling left. Adapted with permission from⁹⁷. Copyright 2019 John Wiley & Sons.