Artificial Chameleon Skin
A thin, chameleon-like material that changes color on demand could offer some intriguing possibilities for a new generation of display technologies, camouflage, and sensors capable of detecting even the smallest structural defects.
Rather than using traditional optic s, the color-shifting material operates on the same principle as diffraction gratings – evenly spaced slits that spread light into its component colors. But instead of slits, the scientists etched tiny ridges into a single thin layer of silicon approximately 120 nanometers thick. The ridges reflect a specific wavelength of light depending on the size of the spaces in between them. Then it was noted that the spaces (and therefore the color) could be shifted by flexing or bending the material. So the bars were partially embedded into a flexible layer of silicone to create a “skin” that is very thin, perfectly flat and easy to fabricate. It also reflects extremely pure, vibrant colors – from green to yellow to orange to red – with 83 percent efficiency.
As a display, the surface would be ideal for outdoor presentations or entertainment venues. In industrial or architectural applications, color-changing sensors could be used to indicate stress or structural fatigue on equipment, bridges or buildings. The next step will be to scale the process for larger commercial applications.
For information: Connie Chang-Hasnain, University of California Berkeley, Electrical Engineering and Computer Science, 263M Cory Hall #1770, Berkeley, CA 94720; phone: 510-642-4315; fax: 510-643-7345; email: firstname.lastname@example.org; Web site: www.berkeley.edu or http://light.eecs.berkeley.edu