Your Summer Clothes Don't Keep You Cool, But This Plastic Fabric Will
People started wearing clothes to keep warm. In the summer, we don't want to be warm. We want to be cool. And that's why summer fashion is just plain backwards.
A team of Stanford researchers say they have figured out what to do about it, according to research published on Thursday in the journal, Science.
Commercial threads are designed fundamentally to be opaque to visible light, or in other words, not see-through. One consequence is they are also opaque to infrared light—which is what scientists call heat—and trap it near the body. Cotton fiber is a particularly strong heat absorber, which is exactly what nobody wants when temperatures rise.
The Stanford team has developed a plastic fabric that would provide tasteful social cover and let body heat dissipate, almost as if people were wearing only what they entered the world with. It's a modified polyethylene—think kitchen plastic wrap, but riddled with nanoscale pores that change its appearance from transparent to white-ish. The pores scatter visible light, rendering the material solid to our eyes. But body heat passes right on through, as seen in these images produced by the lab:
There's more to cloth than that, though. To make their material work more like regular fabric, the scientists added a chemical that attracts moisture (sweat) and whisks it away. To give it more structure, they then made a three-ply version, wedging a thin cotton mesh between two sheets of polyethylene. This chart from the research shows how the temperature of skin varies with what's covering it. Adding the cotton mesh (below, "PDA-nanoPE-mesh") affects the performance of the material, but it's still two degrees Celsius cooler than cotton:
Yi Cui, a Stanford associate professor and a co-author of the research, said he and his colleagues may need an additional six months to turn the material into a woven fiber that can be used in clothing before they can begin to test fabrics on people. Within two years, he said, the material may be ready for commercialization.
The researchers are after something more than consumers' personal comfort. If people wore cooler duds, they'd require less air conditioning. Less AC means less energy used, less money spent, and less electricity-related carbon dioxide pollution produced. A commentary on the study, also published in Science this week, suggests that heat-venting clothing could save up to 45 percent of the energy used to cool buildings.
Before that's ever realized, there will be plenty of additional questions, including: How do you wash it?