Abstract
Electric properties of polymer materials are reviewed especially from a viewpoint of electronic conduction. Carrier in jection is a major electronic carrier source in insulating polymers. The barrier height for injection is generally as high as 2 to 3 eV and the surface states affect the interface between polymer and metal. Space charges often accumulate in polymers or at the interface of polymer-metal and polymer polymer. They modify the internal electric field so strongly that space charge effects are significant not only in the electrical conduction and breakdown phenomena, but also in the piezoelectricity of polymers.