polymeric films exhibiting piezoelectric properties have such properties enhanced by being subjected to improved poling apparatus of the present invention comprising a textured corona discharge electrode roller oscillating over the polymeric film , preferably polyvinylidene fluoride , while the film is simultaneously slowly transported on a rotating drum . the electrode continuously discharges corona through the film while sweeping back and forth thereover . comparatively low voltages are employed and dielectric breakdown of the film is substantially non - existent . a protective reuseable co - film is preferably interposed between the oscillating electrode and film to be poled .