Piezoelectricity and pyroelectricity in ferroelectric polymers

The piezoelectric and pyroelectric constants of various ferroelectric polymers have been determined as a function of remanent polarization created as a result of poling. The results are compared with predicted activities arising from macroscopic dimensional changes and rigid dipoles. It is shown that the dimensional effect is dominant in the piezoelectric activity of undrawn polymers. In drawn polymers having relatively low Curie point, however, stress-induced changes in dipole orientation through the electro-strictive coupling play an important role. Pyroelectric activity primarily arises from temperature-induced disordering of dipoles.