UC Berkeley engineers have taken inspiration from nature and have created an ultra-thin film that can change colors easily like a chameleon's skin when pulled or twisted.

Connie Chang-Hasnai, professor of electrical engineering and computer sciences and lead researcher of the team, described their material in a study published in the journal Optica, this week.

Researchers have said that this thin-skinned material could be developed into active camouflage on vehicle exteriors, or a new class of display technologies.

The material is very useful, as it could also be used as an early warning system for structural fatigue, by changing color whenever there comes any kind of stress on the critical components on bridges, buildings or the wings of airplanes.

In order to get the job done, the engineers, rather than taking the help of chemical dyes or pigments for absorbing and reflecting light, manipulated the structure of the material. In this case a film of silicon, about a thousand times thinner than a human hair, was used.

The rows of tiny ridges, each smaller than a wavelength of light, were fixed onto the film that would reflect light at different wavelengths, depending upon how far about the ridges are spaced.

With the tuning of the spaces between the ridges, the researchers got a chance to select particular colors for reflection.

The feature also pointed out that the shift in the spaces between the ridges, by flexing or bending the material, would lead to a different wavelength of reflected light.

The scientists at the University of Geneva, earlier this week, revealed that how chameleons change colors. They said that the color-shifting lizard changes the spacing of nanocrystals just under their skin.

Connie Chang-Hasnain said, "We were fascinated by the chameleon's ability to change colors, and the process of mimicking their skin has been exciting. The coolest thing is that you can hold the sample film and stretch it to see the colorful effect".