Dielectric properties of piezoelectric polyvinylidene flouride (PVDF)

Measurements were made of the free dielectric constant and the dielectric loss tangent of piezoelectric polyvinylidene fluoride (PVDF) at frequencies between 1 kHz and 5 MHz and temperatures between − 28°C and + 51°C. Samples of nonvoided and voided PVDF were tested. The dielectric constant increases with increasing temperature and/or decreasing frequency, ranging from about 3 to 11 for the voided material and from about 4 to 14 for the nonvoided material. The dielectric loss tangent (dissipation factor) ranged from about 0.02 at low frequencies and high temperatures to about 0.3 at high frequencies and high temperatures. The voided material was not as 1ossy as the nonvoided material, with maximum values 0.2 for the voided material and 0.3 for the nonvoided material. A slight temperature aging effect was observed; an increase of a few percent in dielectric constant resulted from cycling the samples to 51°C.