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Triple-Scale Structure-Induced Efficient Passive Radiative Cooling Combining Robust Anticondensation
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DOI：10.1021/acsnano.5c03434.png)
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Abstract
En 中文
Passive radiative cooling holds promise for achieving subambient cooling without consuming energy, facilitated by emitting thermal radiation into cosmic space. However, previous approaches, focusing heavily on aligning structural scales with optical properties, have struggled with effective anticondensation, thus limiting their applicability in high-humidity or supercooled conditions. Here, we demonstrate a design that enables efficient passive radiative cooling while maintaining robust anticondensation performance, underpinned by a triple-scale structure comprising microscale polymer particles, submicrometer-scale interparticle gaps, and nanoscale pores on the particle surfaces. This design achieves an efficient sunlight reflectance of 0.98 and high mid-infrared emissivity of 0.91 driven by the triple-scale structure-enhanced Mie scattering and chemical bond vibrations in polymer materials, respectively, enabling a 10.9 degrees C subambient cooling under direct sunlight at similar to 40% relative humidity. Notably, even at a high relative humidity of similar to 70%, our design still manifests an average cooling of similar to 4 degrees C compared to ambient temperature, quite exceeding that of traditional radiative cooling materials. This is attributed to the robust anticondensation performance characterized by a maximum droplet shedding radius of similar to 47.6 mu m and a condensation droplet coverage of similar to 32.4%, attributed to the triple-scale structure-induced larger Laplace pressure force and smaller adhesion. Moreover, our design demonstrates robust durability, encompassing self-cleaning performance via condensing droplets, thermal stability below 500 degrees C, and antiultraviolet radiation above 100 h, which exhibits potential applications in thermal management in various extreme scenarios.
Keywords:
passive radiative cooling
triple-scale structure
anticondensation
droplet dynamics
self-cleaning