Figure 7.

2D material nanocoatings and devices with skin-mimicking capabilities. To mimic high stretchability of human skin, stretchable 2D material nanocoatings/devices with hierarchical crumple/wrinkle structures have been fabricated by various approaches, such as A. “balloon-blowing”, B. two-step substrate deformation, and C. back-infiltration of elastomer. Adapted with permission from^{17, 107, 108}. Copyright 2018, 2019 American Chemical Society, John Wiley & Sons. Based on the pre-textured 2D material nanocoatings, stretchable 2D material barriers possess exceptional impermeability to various small-molecule organic liquids (D.) and demonstrate high fire retardancy (E.). The stretchable protective skin allows the soft robots to work in fire scene (F.) and prevents nitrile gloves to be ignited under the contact with ethanol flames (G.). Adapted with permission from^{108, 109}. Copyright 2018, 2019 American Chemical Society, John Wiley & Sons. Moreover, stretchable tactile sensors were fabricated by the use of 2D materials, and the skin-like 2D material devices were able to differentiate the strain and pressure signals, including pressure-insensitive strain sensor (H.), strain-insensitive pressure sensors (I. and J.) with fascinating application in surgical robots (J.). Adapted with permission from^{17, 113, 114}. Copyright 2019 American Chemical Society.