Researchers have created thin coatings that react mechanically and chromatically to specific vapors, drawing inspiration from the chameleon’s skin’s adaptive iridophores, or nanophotonic structures. According to the experts, the resulting “structural-color actuators” could be used for “sensing, communication, and disguise” in soft robotics. These actuators can move and change color in response to changes in the chemical environment.
Recent years have seen significant advancements in the study of soft actuators for soft robotics, including polymer-based soft actuators that can move and change form. Many systems have tried to include color in the mix by integrating integrated microfluidics to pump dyes into the actuators to enable color shifts and camouflage. However, some of these systems must be more active to react and photobleach-prone, making them less than optimal for truly adaptive coloration.
The team turned to a different coloration model: the structural hues used by chameleons and other animals in nature for concealment and sex displays. Guanine nanocrystals embedded in structures on the lizard’s skin called iridophores contribute to the legendary ability of these reptiles to change color to blend into their environment rapidly. The lizards can actively change the spacing between the nanoparticles, which causes the interference patterns of the scattered light to change as well, leading to color shifts that can occur almost instantly. The nanoparticles operate as photonic crystals.
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