Reconfigurable\nMicro- and Nano-Structured Camouflage\nSurfaces Inspired by Cephalopods

Abstract

Wrinkled\nsurfaces and materials are found throughout the natural\nworld in various plants and animals and are known to improve the performance\nof emerging optical and electrical technologies. Despite much progress,\nthe reversible post-fabrication tuning of wrinkle sizes and geometries\nacross multiple length scales has remained relatively challenging\nfor some materials, and the development of comprehensive structure–function\nrelationships for optically active wrinkled surfaces has often proven\ndifficult. Herein, by drawing inspiration from natural cephalopod\nskin and leveraging methodologies established for artificial adaptive\ninfrared platforms, we engineer systems with hierarchically reconfigurable\nwrinkled surface morphologies and dynamically tunable visible-to-infrared\nspectroscopic properties. Specifically, we demonstrate architectures\nfor which mechanical actuation changes the surface morphological characteristics;\nmodulates the reflectance, transmittance, and absorptance across a\nbroad spectral window; controls the specular-to-diffuse reflectance\nratios; and alters the visible and thermal appearances. Moreover,\nwe demonstrate the incorporation of these architectures into analogous\nelectrically actuated appearance-changing devices that feature competitive\nfigures of merit, such as reasonable maximum areal strains, rapid\nresponse times, and good stabilities upon repeated actuation. Overall,\nour findings constitute another step forward in the continued development\nof cephalopod-inspired light- and heat-manipulating systems and may\nfacilitate advanced applications in the areas of sensing, electronics,\noptics, soft robotics, and thermal management.