Separate contributions to the pyroelectricity in poly(vinylidene fluoride) from the amorphous and crystalline phases, as well as from their interface

New selective poling schemes for polar semicrystalline polymers are described, and appropriate poling fields and temperatures are specified. In the following investigation of the pyroelectric response and the thermally stimulated depolarization (TSD), poly(vinylidene fluoride) is used as an example for a semicrystalline ferroelectric polymer. It is shown that the amorphous and the crystalline phase, as well as the interface between them contribute to the pyroelectric effect. From dynamic pyroelectrical measurements and TSD experiments, the permanent polarization of the dipoles in the crystalline phase, the frozen-in polarization of the dipoles in the amorphous phase, and the effect of the excess charges of the Maxwell-Wagner interface polarization can be identified. With the proposed selective poling schemes (poling temperatures below and/or above the glass transition temperature, as well as poling fields lower and/or higher than the coercive field), it is possible to clearly separate the respective contributions to the pyroelectric effect. (C) 1999 American Institute of Physics.