Stanford University engineers have created a low-cost plastic material that could become the basis for clothing that cools the wearer, reducing the need for energy-wasting air conditioning. The material works by allowing the body to discharge heat in two ways that would make the wearer feel nearly 4 degrees Fahrenheit cooler than if they wore cotton clothing. It cools by letting perspiration evaporate through the material, something ordinary fabrics already do. But the Stanford material provides a second mechanism: allowing heat that the body emits as infrared radiation to pass through the plastic textile. To develop the textile, the researchers blended nanotechnology, photonics, and chemistry to give polyethylene - the clear, clingy plastic we use as kitchen wrap - a number of characteristics desirable in clothing material. It allows thermal radiation, air, and water vapor to pass right through, and it is opaque to visible light.