Scientist discover photochromatic wool

Australian researchers have developed woollen clothing that changes colour in the sun and blocks harmful UV rays. While other researchers have already developed colour-changing cotton and glass, this is the first time such photochromatic technology has been applied to wool. Tong Cheng, a PhD student from Deakin University , has created a polymer that is mixed with the photochromatic dye to trap its pigments. The polymer-dye mix is then used to colour the wool.

The polymer also absorbs harmful UV rays and increases the fabric's sun protection factor. When the dyed fabric is exposed to sunlight, the dye molecules change structure, changing the appearance of the dyed wool. The researchers have so far developed white fabric that turns blue or red. According to supervising researcher Dr Rex Brady, the tiny pores are the key to the achievement. "Tong Cheng had to ensure that the pores in the polymer were just the right size. If they were too large for example, the dye would seep out."

The colour-change process also has to be swift, to ensure speedy sun protection, which the researchers say they have achieved in 2-3 seconds. Cheng says the treated wool product looks and feels like other wool products. "It is impossible to notice the difference between normal wool fabric and fabric coated with the polymer. The fabric maintains its softness and drape and the colour is preserved when washed," she says.

The technology has the potential for both novelty fashion and function in the future. Cheng says she's looking forward to seeing woollen t-shirts that only reveal their patterns when worn outside or under certain lighting. But she says swatches of fabric could also be produced and held out in the sun each morning to determine if sun protection cream and clothing are required. The research has been funded by the China-Australia Wool Innovation Network.