An aerogel made from gelatin and DNA surpasses 100% solar reflectance, yielding exceptional radiative cooling, a new study reports. It is also biodegradable. The novel approach paves the way for high-performance next-generation radiative cooling materials, promoting environmentally friendly advancements in the field. Sustainable, energy-efficient, and environmentally conscious cooling technologies are crucial for adapting to our rapidly warming world. Compared to traditional refrigeration systems, passive radiative cooling technologies consume less energy and emit fewer greenhouse gasses, making them a potentially sustainable thermal management strategy. However, many passive cooling strategies rely on polymer materials that lack long-term stability, are not recyclable, or contain harmful compounds. Moreover, petrochemical-derived polymers often face challenges when used for optical daytime radiative cooling due to intrinsic solar absorption. Leveraging interactions between DNA and gelatin (GE), Jian-Wen Ma and colleagues present a photoluminescent biomass aerogel with a large cooling effect. Ma et al. found that combining DNA and GE into an ordered layered aerogel structure produced a passive radiative cooling material that achieves an average visible light reflectance of 104.0% through unique fluorescence and phosphorescence behaviors. The design is capable of cooling ambient temperatures by 16ºCelsius under high solar irradiance. In addition, the authors show that these aerogels – fabricated exclusively from biomass feedstock and efficiently at scale through water welding – boast impressive reparability, recyclability, and biodegradability without adverse environmental impact during use. "Passive radiative cooling stands out as a major innovation strategy for energy conservation efforts. However, it is crucial to not overlook the environmental implications of this approach. Mitigating environmental pollution by adopting biopolymer-based [radiative cooling materials] is one approach," write Changyu Shen and Xianhu Liu in a related Perspective, which also highlights several of the new material's limitations.
For reporters interested in research integrity issues, coauthor Hai-Bo Zhao notes, "recent efforts in my field have focused on enhancing transparency through open data and reproducibility initiatives. These measures are critical for ensuring research integrity. I believe there should be more emphasis on robust peer-review processes and the establishment of standardized protocols for research methodologies."
