The ultrathin coating is also self-cleaning and can cool ambient room temperature. A material that’s more transparent than glass without sacrificing privacy sounds like an impossibility, but an ultrathin film designed by researchers at Germany’s Karlsruhe Institute of Technology (KIT) does just that. The new polymer-based microphotonic multifunctional metamaterial (PMMM) owes its abilities to silicone “micro-pyramids,” each one-tenth the diameter of a human hair, and is more transparent than a w...