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 d₃₁^M 0.6 × 10^–11 C/N (at room temperature) and 4.6 × 10^–13 C/N (below glass transition temperature), and d₃₃^M –1.4 × 10^–11 C/N and –0.5 × 10^–11 C/N, respectively, reproducing well the observed temperature dependence of these constants.