Colour in the sun

Wool clothes that change colour in the sun and provide protection from harmful UV rays could be the next fashion trend thanks to new research at Deakin University.

Tong Cheng, a PhD student with Deakin’s Centre for Material and Fibre Innovation, has developed a way of colouring wool with photochromic dye.

Photochromic products undergo a colour change when exposed to UV radiation. The problem is that photochromic dyes and wool are incompatible when applied by traditional dyeing methods.

But now, Cheng has created a polymer that can hold the photochromic dye and be applied to the surface of wool fibres. The special polymer contains a huge number of tiny pores that trap the dye.

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. It was also important that the polymer allowed the colour change for the dye to take place quickly.

'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. We could soon be seeing wool T-shirts that only reveal their patterns when worn outside or in a disco with black lights. Having patterns appear this way also opens up novel marketing and fashion opportunities,'  said Cheng.

Cheng said that an unexpected bonus with the polymer coating was its UV protection quality. 'We have found that the polymer absorbs harmful UV rays in sunlight. When applied to wool, these polymers enhance the natural UV absorption of the fibre, further increasing the SPF (Sun Protection Factor) afforded by wool garments. Initial tests have shown these rays are almost totally blocked,' Cheng added.

Cheng’s research has been funded by the China-Australia Wool Innovation Network (CAWIN) program — a partnership between Australian Wool Innovation (AWI) and Deakin University.

The significance of her work has been recognised with two recent awards - Materials Australia’s prestigious 2006 Borland Forum Award and the 2007 AWI/DWI Award for Excellence in Wool Science.