Bio-inspired fibres change colour when stretched

Materials scientists from the University of Exeter have developed colour tunable, photonic fibres that change colour when stretched, a breakthrough which they believe could lend itself toward smart fabrics that visibly react to heat or pressure.

The new fibres are based on a structure found in nature, namely the bastard hogberry plant, pictured. Although the plant cannot change colour, the researchers found that by combining its structure with an elastic material, they were able to create an artificial version that passes through a full rainbow of colours as it's stretched. "For our artificial structure, we cut down the complexity of the fruit to just its key elements," said principal investigator Peter Vukusic. "We used very thin fibres and wrapped a polymer bi-layer around them. "That gave us the refractive index contrast, the right number of layers, and the curved, cylindrical cross section that we needed to produce these vivid colours." Vukusic believes the technology could lend itself to smart sports textiles that change colour in areas of muscle tension, or that sense when an object is placed under strain as a result of heat. The work was carried out in partnership with Harvard University in the US.