Daytime radiative cooling presents an exciting new strategy for combating global warming, because it can passively cool buildings by reflecting sunlight and utilizing the infrared atmospheric window to eject heat into outer space. Recent progress with novel material designs showed promising subambient cooling performance under direct sunlight. However, large-scale implementation of radiative cooling technologies is still limited by the high-cost and complex fabrication. Here, we develop a nanoporous polymer matrix composite (PMC) to enable rapid production and cost reduction using commercially available polymer processing techniques, such as molding, extrusion, and 3D printing. With a high solar reflectance of 96.2% and infrared emissivity > 90%, the nanoporous PMC achieved a subambient temperature drop of 6.1 °C and cooling power of 85 W/m 2 under direct sunlight, which are comparable to the state-of-the-art. This work offers great promise to make radiative cooling technologies more viable for saving energy and reducing emissions in building cooling applications.

Initiated chemical vapor deposition (iCVD) of poly(glycidyl methacrylate) from supersaturated monomer vapor is reported. Rapid film growth rates, up to 600 nm/min, were observed. Films grown from supersaturated monomer exhibited distinct surface undulations. The temporal evolution of surface features during film growth was studied and is explained by monomer condensation followed by droplet coalescence and film growth. High droplet densities were observed at the early times and are attributed to rapid polymerization of monomer within condensed liquid nuclei. Droplet nucleation resulting in surface undulations can be avoided by first depositing a thin, cross-linked film from ethylene glycol diacrylate monomer followed by deposition of supersaturated monomer vapors.

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Rebaudioside (Reb) D and M are the recent focus of the food industry to address the bitter taste challenge of Reb A, which is the most commonly used steviol glycoside in natural sweetener stevia. This study evaluated the sensory characteristics of Reb A, D, and M, compared to 14% (w/v) sucrose, using a consumer panel and explored the relationship between 6-n-Propylthiouracil (PROP) taster status (i.e., non-tasters, medium tasters, supertasters) and the perceived intensity of sweet and bitter tastes of the three steviol glycosides. A total of 126 participants evaluated the intensities of in-mouth, immediate (5 s after expectorating), and lingering (1 min after expectorating) sweetness and bitterness of 0.1% Reb A, D, M, and 14% sucrose and described the aftertaste of the sweeteners by using a check-all-that-apply (CATA) question. The results showed that in-mouth sweetness and bitterness of Reb D and M were not significantly different from sucrose, unlike Reb A which showed significant bitterness. However, Reb D and M showed more intense lingering sweetness than sucrose. The CATA analysis resulted that Reb D and M were closer to positive attribute terms and also to sucrose than Reb A, but Reb D and M were still considered artificial, which may cause them to be perceived negatively. When comparing among PROP taster groups, no significant differences in the perceived sweetness and bitterness of the three steviol glycosides were found. This study generates important information about Reb A, D, and M for the food industry, especially working with products formulated to deliver reductions in sugar using a natural high-intensity sweetener, stevia.