Organotin Piezo- and Pyroelectric Polymer Films

Abstract

Since the early work on the piezoelectric effect in polymeric materials, many types of polymers have been shown to be piezoelectrically active. Of the synthetic polymers, poly-(vinylidene fluoride) (PVF2) in s and γ crystal forms, has the highest piezoelectric constant, d31 = (2 – 5) × 10-11 CN-1. The piezoelectricity in polymers may also be roughly related to the dielectric constant.2 The dielectric constant for PVF2 is 8.0 for the s and γ crystal forms. In the s and γ crystal forms the dipoles can be oriented to a sufficiently high degree, whereas in the α crystal form the chain has a small dipole moment, the overall dipole moment in a unit cell is zero, and no piezoelectric activity is found.