Historically, polymers are prized as electrical insulators:  consider polyethylene, which is still universally employed as the insulator for high-voltage cables.  However, in the 1970s, MacDiarmid, Heeger, and Shirakawa (2000 Nobel Laureates in Chemistry) discovered that certain polymers were actually semiconducting, and when properly doped, could even be used as electrical conductors.  In the ensuing decades, extensive research has been undertaken worldwide on semiconducting and conducting polymers, and commercial products ranging from antistatic coatings to consumer electronics displays are now on the market.  In some cases, these devices are made possible by the processing advantages of polymers over conventional conductors (such as metals), but in other cases, the unusual behavior of semiconducting and conducting polymers allows entirely new types of devices to be developed.