American Association for the Advancement of Science
Online — Inspired by organisms that can change the nature of their skin, such as octopuses, researchers have developed a device with tunable infrared reflectivity. The advancement could help hide objects from infrared (heat-sensing) cameras, among other applications.
Infrared light is a part of the electromagnetic spectrum that’s not visible to the human eye but is felt in the form of heat.
Controlling light at this wavelength is desirable for a wide range of applications, for example in regulating the temperature of buildings or for developing camouflage platforms that might be useful in military operations.
To date however, it has been difficult to develop a camouflage device that can adapt to a changing environment, while maintaining other desirable qualities, such as repeated use and a low working temperature range.
Here, Chengyi Xu and colleagues took inspiration from cephalopods (such as squid, octopuses, and cuttlefish), which feature skin containing clusters of adaptive chromatophore pigment cells, as well light-reflecting cells, that can expand and contract.
The degree of expansion and contraction dictates how much light of variable wavelengths is reflected.
Using a combination of special electrodes, wrinkled membranes and an infrared-reflective coating, the researchers created a synthetic device that mimics cephalopod skin. As the membrane expands through the application of an electric current, the more light of a given wavelength is reflected.
Xu et al. created a squid-shaped version of the device and analyzed its ability to “hide” from an infrared camera; they report that altering the reflectance of the device so that its temperature changed by a mere 2 °C was sufficient to mask its existence from an infrared camera.
ED. Note: The Eureka news release online at: https://www.eurekalert.org/pub_releases/2018-03/aaft-edb032718.php shows a video of the effect along with a caption:
“A video of the device developed by Xu et al., which possesses a relatively small active area with a wrinkled surface before electrical actuation, but a larger active area with a flattened surface after electrical actuation. This material relates to a paper that appeared in the 30 March 2018 issue of Science, published by AAAS. The paper, by C. Xu at University of California, Irvine in Irvine, Calif., and colleagues was titled, “Adaptive infrared-reflecting systems inspired by cephalopods.”
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