Advanced new fibres are reportedly able to change colour using a concept similar to light-sensitive spectacle lenses which darken when exposed to sunlight.

The fibres, created from materials known as electrochromic polymers, change colour in response to an electric current. When voltage is applied, the polymers’ electrons are raised to a higher energy level. In this state the fibres absorb light of different wavelengths, and the colour changes.

To date, Gregory Sotzing, a professor of polymer and organic chemistry at the University of Connecticut and his colleagues have developed fibres that can turn from orange to blue and from red to blue. Eventually Sotzing aims to conquer the entire spectrum of visible colour.
In theory these fibres and a small number of thin metal wires could be woven together in a crisscross pattern that resembles pixels. A small battery and controller attached to the wires could then change the electric field around each pixel of fibre, changing the colours to create a pattern that matches the wearer's environment.

In addition to changing colour when electricity is applied the polymers can also change colour in response to changes in the environment.

Therefore, the fibres could possibly be used as sensors in the food and security industries. For example, packaging could potentially change colour when an internal sensor detects rotten or contaminated food, or the sensors could change colour when the fibres detect harmful chemicals in the air. The fibres could also have applications for flexible displays, such as computer screens, that do not become distorted when pressed.