Stretchable and Hydrophobic Electrochromic Devices Using Wrinkled Graphene and PEDOT:PSS

Figure 4

(a) Water contact angle measurements on polyurethane, pristine graphene, and wrinkled graphene. Wrinkling results in controlled formation of roughness in graphene and subsequent increase in its water contact angle values. (b) Hydrophobic nature of the electrochromic device, shown by a water droplet placed on the device, exhibiting a contact angle of 110°  ± 2° in oxidized (bleached) and reduced (blue) states. (c) SEM image of the wrinkled graphene at an applied radial prestrain of 30%. The wrinkles have a periodicity of ~1.95 μm, which is on the same order of magnitude with our calculated wavelength of 2.293 μm.

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