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Next-gen coating mimics clouds to manage heat, evade detection

Next-gen coating mimics clouds to manage heat, evade detection
Source: interestingengineering
Author: @IntEngineering
Published: 7/1/2025

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Researchers at Finland’s Aalto University have developed an innovative wafer-thin “cloud” metasurface coating that can dynamically switch between bright white and deep grey states, enabling surfaces to either cool by reflecting sunlight or heat by absorbing it, all while remaining nearly invisible to infrared (thermal) cameras. This dual-function coating mimics the behavior of cumulus clouds, adapting its optical properties to manage heat passively and without energy input. Unlike traditional white paints that cool by scattering sunlight but become conspicuous in thermal imaging, or black surfaces that absorb heat but emit strong infrared signals, this metasurface maintains very low mid-infrared emissivity (8–13 microns), effectively camouflaging heat signatures in both modes. The coating’s unique performance arises from a disordered array of metallic nanostructures that manipulate light through multiple scattering and “polarizonic reflection.” In the white state, solar photons are reflected back into space, providing radiative cooling under full sun, while in the grey state,

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materialsnanotechnologysmart-coatingsthermal-managementinfrared-camouflageenergy-efficiencymetasurfaces