Scientists have been striving to tackle the accelerating climate crisis by developing novel ways to develop sustainable cooling materials.
Recently, a team of researchers from Sichuan University in China has devised an aerogel composed of gelatin and DNA that surpassed 100 percent solar reflectance.
Additionally, an official statement by the American Association for the Advancement of Science (AAAS) noted that the aerogel is biodegradable and provides exceptional radiative cooling.
Aerogel crossed over 100% solar reflectivity
Jian-Wen Ma, the first author of the study researching and developing the aerogel material told Interesting Engineering that the material has a reflectivity of 104 percent in the visible region which is brought by the photoluminescence effect.
“The reflectivity is obtained by testing with a post-spectroscopic UV/VIS/NIR device,” he told IE .
“The luminescence of the aerogel originates from the tightly cross-linked network formed by gelatin and DNA, which allows the chromophores to come together and inhibit the non-radiative leaps of the system.”
In simple terms, the cooling material possesses the ability to reflect a lot of sunlight due to its special layered design and its unique way of glowing when exposed to light.
Not only is the material biodegradable but is also reparable, and recyclable, presenting an environmentally friendly alternative to traditional cooling materials.
The aerogels have been fabricated from biomass raw materials – gelatin and DNA, with excellent repairability, recyclability, and biodegradability, Ma told IE . “This is an environmentally friendly cooling material.”
Cooling material forged from biomass feedstock
Particularly, the material was forged from biomass feedstock using a process called water welding. It can cool ambient temperatures by 16 degrees Celsius under high solar irradiance and is both reparable and biodegradable.
Alluding to the preparation process, Ma said that the gelatin and DNA were designed by the sol-gel method via a freeze-drying process to obtain structurally homogeneous aerogels.
“The multi-stage layered structure of the aerogel allows for multiple scattering/reflection of sunlight, which effectively improves solar reflectivity,” Ma told IE .
This new approach aims to overcome the challenges of conventional refrigeration systems which consume more energy and emit more greenhouse gases. Therefore, using biopolymer-based materials delivers long-term stability and minimal environmental impact.
‘Biodegraded by microorganisms in the natural environment’
The cooling material was successfully tested under different weather conditions such as sunny, cloudy, and overcast.
Additionally, the biomass aerogel can be biodegraded by microorganisms in the natural environment, the first author noted.
The recycling of aerogel can be achieved through the process of high-temperature dissolution – re-gelation – and freeze-drying.
Scientists are now exploring potential practical applications for the aerogel.
Ma told IE that the use of this aerogel in different industries may present unique challenges.
“We are confident that these challenges can be addressed through further research and experimentation.”
“Passive radiative cooling stands out as a major innovation strategy for energy conservation efforts,” Changyu Shen and Xianhu Liu noted in the Related Perspective as per the statement.
“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.”
The study was published earlier today [July 4, 2024] in the journal – Science .
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