Inverse piezoelectric effect and electrostrictive effect in polarized poly(vinylidene fluoride) films

TLDR: The piezoelectric stress coefficient and electrostriction coefficient for unpoled and poled films of polyvinylidene fluoride have been determined by applying a sinusoidal electric field and detecting stresses with the same and double frequency as the applied field, respectively as mentioned in this paper.

Abstract: The piezoelectric stress coefficient and electrostriction coefficient for unpoled and poled films of polyvinylidene fluoride have been determined by applying a sinusoidal electric field and detecting stresses with the same and double frequency as the applied field, respectively. The piezoelectric coefficient shows a hysteresis with the cyclic change of the d.c. bias field. Under the poling field, the dipoles in polymers are preferentially oriented in the direction of the field, thus producing a residual polarization associated with a residual stress. Both coefficients increase with increasing temperature. A phenomenological interpretation for the piezoelectricity in poled polymers is given in terms of electrostriction and residual stress.