How cutting edge fabrics keep you cool on hot days

Are we going to see employers chucking out the office air conditioning and issuing their staff with new clothes instead?

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It could happen. Jonathan Tong, researcher at Massachusetts Institute of Technology (MIT) is one of the people working on fabrics that will draw body heat away from the body far more efficiently than any current material.

The secret is infra-red light

Most clothes are opaque to light. That is generally useful if you don’t want everyone to be able to see through your clothing. However, they’re also opaque to infrared radiation, which makes the body warmer. This is great when it’s chilly, but not so great when it’s sweltering as they don’t disperse your body heat.

Tong and his colleagues set out to design a material that would be transparent in the infrared spectrum, so it would not capture body heat, which is transmitted in this spectrum. Currently, cotton and polyester materials make up nearly 80 per cent of all textile production. These materials only lose roughly 1 per cent of the infrared heat that strikes them.

The team have been looking for materials that can be mixed with cotton and polyester to transform them into fabrics that have cooling properties.

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Two candidate materials

Polyethylene may be a strong candidate. It is much less absorbent of infrared light because of its composition; it has molecules of different lengths.

The second candidate is nylon. The 1950s favourite seemed about to revolutionise the workplace earlier, when drip-dry nylon shirts were invented. After a brief spate of popularity, these were soon relegated to the laundry bin of clothes history because nylon made people hotter in hot climates and wasn’t warm enough to wear without an undervest in colder climates.

Is this once-promising material about to make a comeback? It has a similar structure to polyethylene, so it should be possible to combine it with cotton or polyester to create a material that is opaque but transmits infrared heat better.

Clothes are not the only potential application of this kind of new material. Tensile fabric canopies like those at http://signaturestructures.com/ made of this fabric could be used to replace roofing in some situations, such as summer classrooms in schools.

The roof would keep people cool and reduce the need for electricity-hungry air conditioning.