Researchers at the University of California Berkeley recently created a super thin new material that changes color when flexed or bent.
This new artificial skin, the first of its kind, could find a variety of applications, including for building safety, in entertainment and even for camouflage.
Colors we normally see around us, such as in paint and fabrics, happen when white light strikes their surface. They are the result of chemistry, with each chemical composition absorbing various wavelengths of light. When chemical compositions change, so do colors, such as leaves in fall.
However, the solution for color-changing properties in this artificial skin happens for entirely different reasons. In their research, engineers cut rows of ridges on a layer of semiconductor silicon a thousand times thinner than a single strand of hair. Each of those ridges reflect a specific wavelength of light. This is similar to how certain butterflies and beetles change their colors in nature. As the silicon is bent or flexed, the ridges reflect certain colors and change when the structure of the material changes, becoming green, yellow, orange and red.
"This is the first time anybody has made a flexible chameleon-like skin that can change color simply by flexing it," says Connie J. Chang-Hasnain, co-author of the study. "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."
Researchers demonstrated their new material with a one-centimeter square layer of silicon. However, they hope to scale up their design to larger sizes so that their materials are useful in commercial applications.
So what sort of applications would this material work with? It would work well with outdoor entertainment displays: its properties could create dynamic color presentations unlike any we've seen before.
The material would also be useful for military applications, such as for camouflage. Imagine vehicle exteriors that are capable of changing their color to better match their surroundings.
Finally, the material is suitable for use in building safety. The silicon could be used as sensors and placed along structures such as bridges, airplanes and buildings, changing color when any kind of damage or structural stress appears.
"The next step is to make this larger-scale and there are facilities already that could do so," says Chang-Hasnain. "At that point, we hope to be able to find applications in entertainment, security, and monitoring."
