Rotation of microspheres in a vertically changing external magnetic field. The color is switched between on (blue) and off states. Video courtesy Yin lab, UC Riverside
In the future, signs will be instantly rewritable and walls will change color at the flip of a switch. A research team at the University of California at Riverside has created a new magnetically activated, instantly and reversibly color-changing material with potentially groundbreaking applications. The technology is based on that used by colorful birds, beetles, and butterflies: instead of static pigments, the material employs "structural color," which depends on the interference effects of light.