Hay Think learned from the Nanjing University Thermal Control Center on December 9 that the center has developed a new material that uses the principle of radiant cooling to achieve a cooling effect of 5 to 7 degrees Celsius below the ambient temperature. The relevant results were recently published in the international academic journal "Nature Nanotechnology".
According to Li Duo, co-first author of the thesis and a master's student at Nanjing University, the scientific name of the new material is "Polymer Nanofiber (es-PEO) Film". The research team uses micro-level hierarchical design to allow the material to reflect sunlight efficiently and pass Radiation heat dissipation.
Zhu Jia, the corresponding author of the paper and a professor at Nanjing University, said that in the past, limited by materials and preparation processes, the radiation band of most polymer materials covered the entire mid-infrared band. While radiating heat outward, the material itself would also absorb heat, so The heat dissipation effect is not ideal.
"We found that the vibration peaks of the chemical bonds of polyethylene oxide (PEO) overlap with the main band channels of thermal radiation." Zhu Jia said, "In layman's terms, PEO materials can make heat "only out but not in"."
According to the theoretical calculation results, the team designed a microstructure that allows the PEO material to reflect sunlight as much as possible, and by improving the traditional electrospinning process, using the "roll-to-roll" fiber collection method, a macro-scale es-PEO film was prepared .
"Roll-to-roll" is a process of preparing large quantities of nano-scale materials on a roll of thin plastic or metal, similar to the production process of traditional fabrics, and its biggest feature is relatively low cost and high output." Ph.D., Center for Thermal Control, Nanjing University Zhu Bin introduced that tests show that under sunlight, es-PEO film can achieve a cooling effect of 5 degrees Celsius below the ambient temperature, and at night it can be about 7 degrees Celsius lower than the ambient temperature.