Color it cool: Hue-changing 'skin' morphs on demand

From CNET

Chameleon-like artificial skin changes colors by applying the slightest force.The Optical Society

Science has finally realized another of our comic book-inspired fantasies with the development of a super-thin synthetic material that can give any surface the hue-shifting capabilities of a chameleon.

Engineers at the University of California at Berkeley developed a silicon film one-thousandth the width of a human hair that can change colors on demand and could one day make its way into displays or sensors that can detect barely perceptible defects in structures like buildings, bridges and aircraft.

"This is the first time anybody has made a flexible chameleon-like skin that can change color simply by flexing it," said Connie J. Chang-Hasnain, a member of the UC Berkeley team that published a paper on the technology this week in the journal Optica.

The film uses a new approach to changing colors that relies on altering the actual surface structure to reflect different visible wavelengths rather than changes to the chemical composition that gives paints and dyes their different colors. Tiny features like ridges or bars thinner than a single wavelength of light are etched into the thin silicon film, with each designed to reflect a very specific wavelength -- and its corresponding color. The color the film reflects can then be changed by subtly flexing or bending the surface.

The color-changing material is made of a semiconducting silicon 120 nanometers thick, but so far has only been made and demonstrated as a 1-cenimeter-square layer."If you have a surface with very precise structures, spaced so they can interact with a specific wavelength of light, you can change its properties and how it interacts with light by changing its dimensions," Chang-Hasnain, chair of the university's Nanoscale Science and Engineering Graduate Group, said in a release.

"The next step is to make this larger-scale and there are facilities already that could do so," said Chang-Hasnain. "At that point, we hope to be able to find applications in entertainment, security, and monitoring."

Imagine a vehicle that changes color depending on location and conditions, or bridges that start to glow red when they develop structural deficiencies, not to mention the ability to put super-thin displays everywhere or become a grand champion of hide-and-seek.

But perhaps the most important potential application of this technology, for me at least, will be to hide in plain sight and scare the breath out of the bully who pushed me to the ground in 1991, pushing his thumbs into the centers of my scrawny pectoral muscles and declaring me a "hypercolor sissy" as I ran away with two hot pink, areola-shaped markings on my color-shifting shirt.