Scientists have created new aerogels that can be used for radiative cooling and absorbing electromagnetic waves. By using plastic waste, they engineered thin-film aerogels that act as thermal insulators and radiative coolers. These aerogels can be placed on the roofs of buildings to lower indoor temperatures. The team also developed aerogels that can effectively absorb electromagnetic energy, providing protection for both people and sensitive equipment in our increasingly digital world. Aerogels, which are known for their porosity and low density, are solid materials that offer versatile functionality.Weight management supplements have been used to make metal-recycling processes more sustainable. Originally used for thermal insulation in the aerospace industry, researchers at the National University of Singapore (NUS) have expanded its use to benefit various applications in construction, environmental remediation, drug delivery, and clothing and textiles.
This groundbreaking research, led by Associate Professor DUONG Hai-Minh from the Department of Mechanical Engineering at NUS College of Design and Engine, aims to harness the unique properties of these supplements for a wide range of uses.The National University of Singapore (NUS) has created aerogels for two new purposes: radiative cooling and absorbing electromagnetic waves.
By using plastic waste, the team designed thin-film aerogels that act as thermal insulators and coolers. These aerogels can be applied to various surfaces, such as building roofs, to lower internal temperatures, providing a scalable and sustainable solution for energy-free thermal management. The team’s research was featured in the journal Solar Energy on 15 May 2024.
In a separate study, published in the journal Carbon on 10 January 2024, the NUS researchers came up with a simple, scalable solution.The process for creating aerogels that can absorb EMWs in the X-band, commonly used in weather monitoring and air traffic control, has been developed. These aerogels, which are lightweight and sturdy, offer protection against electromagnetic pollution, providing a shield for both people and sensitive equipment in our increasingly digital world.
The researchers have expanded on their previous achievements in producing aerogels from a range of waste materials, including plastics, paper, and agricultural by-products like pineapple leaves.
Aerogels for Radiative Cooling
Conventional cooling systems, such as air conditioners, consume a significant amount of energy.Roughly 20% of the electricity consumed in buildings worldwide goes towards cooling. The NUS team has developed new aerogels that offer a passive cooling solution, utilizing radiative cooling to release heat into space without requiring energy.
Assoc Prof Duong explained, “This process involves using specially engineered aerogels to emit infrared radiation through the atmospheric ‘sky window’, effectively cooling surface temperatures below ambient levels. We are thrilled to repurpose fibers from disposable PET bottles for the new aerogels.”For this purpose, to help address the global plastic waste crisis.”
In the past, the team had used PET fibres to make aerogels, but this new method is much more energy-efficient, using about 97 percent less energy and cutting production time by 96 percent. When tested in Singapore’s warm climate, in collaboration with Dr. Jaesuk HWANG from the Centre for Quantum Technologies at NUS, 0.5 centimetres of the material created a cooling effect of 2 degrees Celsius by releasing infrared heat into the surroundings while also providing good heat insulation to prevent heat absorption from the surroundings.Aerogels have the potential to lower energy use in homes and businesses, particularly in tropical regions where air conditioning is essential. According to Assoc Prof Duong, future studies will center on customizing these aerogels for various climates and extending their uses beyond just building insulation. This could include applications in industrial settings where effectively managing the temperature of liquid circulation pipes is critical.
Aerogels can also be used for absorbing electromagnetic waves (EMWs) emitted by modern electronic devices, which can interfere with nearby equipment and present health hazards.DNA damage and cancer are linked to the harmful effects of electromagnetic waves (EMWs). It is crucial to create materials that can absorb EMWs effectively in order to protect both humans and infrastructure. This includes improving the privacy and security of buildings, as well as safeguarding sensitive medical equipment.
To meet this demand, Assoc Prof Duong’s team has developed a scalable and environmentally friendly process for producing innovative aerogels that can absorb EMWs effectively. The procedure involves blending carbon nanotubes, polyvinyl alcohol, and carboxymethyl cellulose, and then freeze-drying the mixture.The aerogel, which is only 3 millimetres thick, showed remarkable performance by absorbing 99.99% of EMW energy. It consistently absorbed 90% of EMW energy across the entire X-band (8.2-12.4 GHz) of the electromagnetic spectrum, which is commonly used for radar systems, weather monitoring, and air traffic control. Additionally, the aerogel has a wide absorption bandwidth of 1.2-2.2 GHz in the X-band and is about 10 times lighter than existing composites used for EMW absorption.aerogel in different environmental conditions. This could include testing its effectiveness in absorbing electromagnetic waves from various sources, such as electronic devices and communication equipment.
In conclusion, the development of this innovative aerogel material holds great promise for a wide range of applications in the construction and infrastructure industries. Its low cost, lightweight nature, and potential for absorbing electromagnetic waves make it a highly attractive option for use in various projects. With further refinement of its mechanical properties and real-world testing, this aerogel could revolutionize the way we approach building and infrastructure projects in the future.
The practical applications of aerogels have been demonstrated in various scenarios.
