ARTIFICIAL SKIN LIKE CHAMELEON

An incredibly thin skin which can change color like chameleon by applying small amount of force.The material  paves the way for  display technologies,colour-shifting camouflage,  and
sensors that can detect otherwise imperceptible defects in buildings, bridges, and aircraft.

This is  a flexible chameleon-like skin that can change colour simply by flexing it.By precisely inscribe  tiny features , smaller than  a wavelength  of  light  onto  a  silicon  film  one thousand
times thinner than  a  human hair,  the  researchers  were  able to select the range of colours the material would reflect, depending on how it was flexed and bent.

Researchers etched rows of ridges onto a single, thin layer of silicon. Rather than spreading the  light into a complete  rainbow, however, these  ridges  or  bars reflect  a  very specific wavelength of light.
Since  the spacing,  or  period,  of  the  bars is  the key  to  controlling  the colour  they     reflect, the researchers realised  it would  be possible  to  subtly shift the  period    and  therefore  the colour  by flexing or bending the material.

Earlier efforts to develop a flexible, colour shifting surface fell short on a number of fronts. Metallic surfaces, which  are  easy  to  etch, were inefficient,   reflecting    only  a portion of the light they received.
The researchers were able to overcome both these hurdles by forming their grating bars using a semiconductor layer of silicon approximately 120 nanometres thick.

Its flexibility was imparted by embedding the silicon bars into a flexible layer of silicone. As the silicone was bent or flexed, the period of the grating spacings responded in kind.
The semiconductor material allowed the team to create a skin that was incredibly thin, perfectly flat, and easy to manufacture with the desired surface properties.