Calculation of piezoelectric constants of poly(vinylidene fluoride)

Summary

Piezoelectric constants of poly(vinylidene fluoride) form I crystal have been calculated to give a good agreement with observed values; d₃₃ = −2.5 × 10⁻¹¹ C/N (observed: −2 × 10⁻¹¹ C/N) and d₃₃ = −2.5 × 10⁻¹³ C/N (observed: ca. 10⁻¹³ C/N). The macroscopic piezoelectric constants have also been calculated using such a model that the piezoelectric crystal form I is embedded in the non-piezoelectric amorphous matrix to be d ^M₃₁ $\doteqdot$ 0.6 × 10⁻¹¹ C/N (at room temperature) and 4.6 × 10⁻¹³ C/N (below glass transition temperature), and d ^M₃₃ $\doteqdot$ −1.4 × 10⁻¹¹ C/N and −0.5 × 10⁻¹¹ C/N, respectively, reproducing well the observed temperature dependence of these constants.