Thermal pulse induced dynamic pyroelectric response and piezoelectric oscillations in polyvinylidene fluoride

Pyro- and piezoelectric properties of films of PVDF poled using two different procedures have been investigated by thermally-induced electrical oscillations—a method consisting of monitoring the response of a polymer resonator to a short pulse of light. The signals observed are interpreted as a superposition of the “time-resolved” pyroelectric response due to the heat flow in the sample and the piezoelectric oscillations produced by thermal stress. Both space-charge and dipolar increments to the pyroelectric charge are observed. Temperature dependences of the sound velocity in the [100] direction, and of pyro-and piezoelectric responses, measured within the temperature range 180-370 K, are reported, and the hysteresis of the pyroelectricity is observed. The results are consistent with most of those reported in the literature.