A team of international researchers has developed a natural fabric that urban residents could wear to counter rising temperatures in cities worldwide, caused by buildings, asphalt, and concrete.
As heatwaves become more prominent, cooling textiles that can be incorporated into clothes, hats, shoes and even building surfaces provide a glimpse into a future where greenhouse gas-emitting air conditioners may no longer be needed in our cities.
Engineers from Zhengzhou University and the University of South Australia say the wearable fabric is designed to reflect sunlight and allow heat to escape, while blocking the sun's rays and lowering the temperature. They have described the textiles in the latest issue of Science Bulletin.
The fabric promises to bring relief to millions of city dwellers experiencing warmer and more uncomfortable temperatures caused by global climate change and fewer green spaces.
UniSA visiting researcher Yangzhe Hou says the fabric leverages the principle of radiative cooling, a natural process where materials emit heat into the atmosphere, and ultimately into space.
"Unlike conventional fabrics that retain heat, these textiles are made of three layers that are engineered to optimise cooling," Hou says.
The upper layer, made of polymethyl pentene fibres, allows heat to radiate effectively. The middle layer, composed of silver nanowires, enhances the fabric's reflectivity, preventing additional heat from reaching the body. The bottom layer, made of wool, directs heat away from the skin, ensuring that wearers remain cool, even in the hottest urban environments.
"In our experiment, when placed vertically, the fabric was found to be 2.3°C cooler than traditional textiles, and up to 6.2°C cooler than the surrounding environment when used as a horizontal surface covering.
"The fabric's ability to passively reduce temperatures offers a sustainable alternative to conventional air conditioning, providing energy savings and reducing the strain on power grids during heatwaves."
Zhengzhou University researchers Jingna Zhang and Professor Xianhu Liu say the technology not only addresses the immediate problem of urban heat islands, but also contributes to broader efforts to mitigate climate change and move towards more sustainable urban living.
It is hoped the technology could be adapted for even broader applications, including construction material, outdoor furniture and urban planning.
While the fabric holds significant promise, researchers say the current production process is costly, and the long-term durability of the textiles needs further investigation and government support before it can be commercialised.
"Whether consumers are willing to pay more for wearable fabrics depend on the cooling effect, durability, comfort and their environmental awareness," the researchers say.