Have you heard of foldable smartphones? How about the flexible television screen that rolls up into a box? Or the ultrathin “wallpaper” TVs that are just millimeters thick? A future with foldable, bendable, flexible and ultrathin electronics is fast becoming our present. The materials responsible for these Consumer goods are typically polymers — plastics — that conduct electricity. To better understand this promising class of substances, scientists at the National Institute of Standards and Technology (NIST) developed a technique that uses light to quickly and accurately test materials’ conductivity — and potentially reveal behavior that other methods could not. Now, the NIST team has demonstr