Pyroelectricity in polyvinylidene fluoride

The pyroelectric behavior of as-received 2-mil polyvinylidene fluoride films was studied as a function of the poling treatment. It is shown that poling induces a thermally reversible electric polarization in addition to an electric polarization which vanishes upon the first heating of the sample. Experimental evidence is given that the reversible polarization involves charge injection from the electrodes in addition to a field-induced structural change (probably the formation of oriented crystalline form I). For short poling times ([inverted lazy s] seconds) the mechanism of charge injection appears to be dominant. Initial results of the temperature and voltage dependence of the dc conductivity and of the temperature dependence of the dielectric loss at 50 and 100 Hz for unpoled and poled 2-mil polyvinylidene fluoride (PVF2) films are presented.