Dielectric absorption in oriented poly(vinylidene fluoride)

The dielectric behavior of poly(vinylidene fluoride) is affected by orientation and crystal modification. The loss peak caused by molecular motion of the molecules in crystalline regions appears at about 70°C (110 Hz) (α 1 absorption) for the α form, and at about 110°C (110 Hz) (α 2 absorption) for the β form. Orientation significantly affects the magnitude of the β absorption which appears at about −40°C. The very high value of the dielectric constant for stretched film is believed to be due to the orientation effect. The γ absorption, which is assumed to be local‐mode absorption, is not so much affected by orientation. An additional loss peak has been found at around 0°C in dynamic mechanical measurements, but the molecular mechanism is unknown.