延伸高分子膜の新しい圧電性

抄録

A new type of piezoelectric effect has been found in certain elongated and polarized films of polymers, viz. poly (vinylidene fluoride), poly (vinylfluoride), poly (vinyl chloride) and poly-carbonate. The newly found piezoelectric polymers possess an mm 2 symmetry and piezoelectric constants d₃₁, d₃₂, d₃₃, d₁₅ and d₂₄ where the z-axis is assigned normal to film surface and the x-axis in the direction of elongation. Piezoelectricity appears in the above polymer films after the following treatment. The films were stretched a few times of the original length at softing temperatures. A static electric field (about 300 kV/cm) was applied to the films along their thickness and the temperature was raised gradually to 60_??_90°C and then slowly cooled. The largest value of g₃₁, and d₃₁ found in poly (vinylidene fluoride) film was about 150 millivolt/gram and 20×10^-8 cgs. esu. The spontaneous polarization in the piezoelectric poly (vinylidene fluoride) film was estimated to be about 2×10^-6 Coulomb/cm².