Polymers are usually the go-to material for thermal insulation. Think of a silicone oven mitt, or a Styrofoam coffee cup, both manufactured from polymer materials that are excellent at trapping heat.

Now MIT engineers have flipped the picture of the standard polymer insulator, by fabricating thin polymer films that conduct heat — an ability normally associated with metals. In experiments, they found the films, which are thinner than plastic wrap, conduct heat better than ceramics and many metals, including steel.