Porous Polymers with Switchable Optical Transmittance for Optical and Thermal Regulation

By Jyotirmoy Mandal, Mingxin Jia, A. Overvig, Yanke Fu, Eric Che, N. Yu, Yuan Yang. 2019

304 citations recorded by the source corpus.

Summary Adaptive control of broadband light is essential for diverse applications including building energy management and light modulation. Here, we present porous polymer coatings (PPCs), whose optical transmittance changes upon reversible wetting with common liquids, as a platform for optical management from solar to thermal wavelengths. In the solar wavelengths, reduction in optical scattering upon wetting changes PPCs from reflective to transparent. For poly(vinylidene fluoride-co-hexafluoropropene) PPCs, this corresponds to solar and visible transmittance changes of up to 0.74 and 0.80, respectively. For infrared (IR) transparent polyethylene PPCs, wetting causes an “icehouse-to-greenhouse” transition where solar transparency rises but thermal IR transparency falls. These performances are either unprecedented or rival or surpass those of notable optical switching (e.g., electrochromic and thermochromic) paradigms, making PPCs promising for large-scale optical and thermal management. Specifically, switchable sub-ambient radiative cooling (by 3.2°C) and above-ambient solar heating (by 21.4°C), color-neutral daylighting, and thermal camouflage are demonstrated.

Subfields: Civil and Structural Engineering, Environmental Engineering, Polymers and Plastics

View Paper: https://www.semanticscholar.org/paper/548cdb62ec748de0ebb5d158b45ca13e4edd58f4