Rubbery fibres have been developed that reversibly change colour when stretched or bent.

Xuemei Sun, Huisheng Peng and their collaborators at Fudan University in Shanghai, China, attached microscopic plastic spheres to elastic fibres that were wound with carbon nanotubes. As the fibre stretches, the spaces between the microspheres increase in size along the length of the fibre, whereas they decrease in the radial direction. This changes the wavelengths of light that are reflected by the fibres, resulting in shifts in colour between red, green and blue as the fibre is stretched and released. The fibres remained stable after 1,000 rounds of stretching and were woven into fabric in various patterns.

Such 'mechanochromic' materials could be used in wearable displays or sensors, the authors say.

Angewandte Chemie http://doi.org/f259np (2015)