A research team led by Ali Javey, associate professor of electrical engineering and computer sciences at the University of California, Berkeley, has created a material that moves quickly in response to light. The team layered carbon nanotubes on a plastic polycarbonate membrane. Light is absorbed into the nanotubes, which convert it to heat and transfer it to the polycarbonate membrane. The plastic expands in response to heat, while the nanotubes do not, causing the two-layer material to bend. “The advantages of this new class of photo-reactive actuator [are] that it is very easy to make, and it is very sensitive to low-intensity light,” says Javey. “A flashlight is enough to generate a response.” Potential applications of the technology include smart curtains that could automatically open or close during the day and light-driven motors or robots that move toward or away from light.