Ferroelectric polymers

In the early 1970s it became clear that the polymer polyvinylidene fluoride is ferroelectric. There have been extensive studies of its properties and of the properties of copolymers of vinylidene fluoride with tri- or tetra-fluoroethylene. This work has led to a fairly complete understanding of the ferroelectric and related properties of these materials. The emphasis in this review is on the studies of these materials that are oriented toward showing that the polymers are indeed ferroelectric, determining the mechanism of polarization reversal, and understanding the origins of the observed piezoelectric and pyroelectric effects. Very recently some odd nylons (nylons with an odd number of carbon atoms in the monomer unit) were recognized to be ferroelectric, and ferroelectric liquid-crystalline polymers have been prepared by attaching ferroelectric liquid-crystal molecules as side chains to polymer backbones. These new findings are included in the review.