Pyro- and piezoelectricity of polyvinylidenefluoride in dependence on the drawing conditions

The pyro- and piezoelectric coefficients p3 and d31, respectively, and the remanent polarization P of PVDF films drawn uniaxially and biaxially under different conditions (draw ratio, temperature) were determined in dependence on the −1 poling field up to 430 MVm⁻¹. While the saturation value of the remanent polarization showed no essential changes, the pyro- and piezoelectric coefficients proved to depend strongly on the drawing conditions, At the saturation value of polarization (Pr = 85 mCm⁻²) the highest values of the pyro- and piezoelectric coefficients (p3 = 45, uCm⁻²K⁻¹ and d31 = 35 pCN⁻¹) were obtained with samples drawn uniaxially at 170 °C. Samples containing chains in transconformation only show strong correlation between pyro- and piezoelectric coefficients and the remanent polarization and dipole orientation, respectively.