By Lizzie Harrett
Although the couple of sun-filled days we’ve had this summer are already becoming a distant memory, there’s good news for those who like to plan their wardrobe a few seasons ahead. Researchers from Stanford University have developed a nifty new material that lets you cool down through letting heat escape, instead of trapping it in like traditional fabrics.
“It’s a very bold new idea,” says physicist Svetlana Boriskina, who was not involved in the study. She added that the consumer market for this material could be massive, “Every person who wears clothes could be a potential user of this product.”
Our skin lets out heat energy in the form of infra-red waves but conventional clothing traps this in between the material and our body, holding in the heat. The team therefore looked at developing clothing that allowed infrared radiation to pass through.
The fabric would need to be transparent only to infra-red waves, but would also need to be opaque as otherwise the material would be see-through, which would somewhat defeat the point of wearing clothes.
The research group found one material that met both requirements. Nanoporous polythene (NanoPE) is a cling-film-like plastic used in lithium-ion batteries which blocks visible light making it opaque, but also letting infra-red radiation escape. Minute pores dotted across the material block visible light by causing it to scatter. The resulting colour is white. However, infra-red radiation passes straight through because it has a larger wavelength than visible light.
They tested the material by placing it on a hot plate that had the same temperature as human skin (33.5 degrees Celsius). NanoPE raised the temperature by just 0.8 degrees whereas conventional cotton caused it to rise by 3.5 degrees.
However, aesthetics are of course everything. While this material may help you keep cool, even the most avant-garde garment wearers could think twice about wearing what is essentially opaque cling film. The team therefore improved it’s wearability by coating it with a water-wicking chemical and layering it with cotton-mesh. The next step is to make it feel like a more traditional textile when being worn.
This fabric may also have an impact beyond just helping people avoid over-heating. Those wearing the product may feel less inclined to reach for the air-conditioning switch, helping to save energy. This could be particularly important if the effects of global warming start to encroach upon us.
Looking forward, the leading author of the study Yi Cui hopes this fabric will catch on, “Within five years, I hope someone will start wearing it,” he stated. “And within 10 years, I hope most people will be wearing it.”