"Ferroelectric Polymers [1] [2] are a group of crystalline polar polymers that are
also ferroelectric, meaning that they maintain a permanent electric polarization that can be reversed, or switched, in an external electric field."
"Ferroelectric polymers, such as polyvinylidene fluoride (PVDF), are used in acoustic transducers and electromechanical actuators because of their inherent piezoelectric response, and as heat sensors because of their inherent pyroelectric response."
"A ferroelectric polymer must contain permanent electrical polarization that can be reversed repeatedly, by an opposing electric field.[4] In the polymer, dipoles can be randomly oriented, but application of an electric field will align the dipoles, leading to ferroelectric behavior. In order for this effect to happen, the material must be below its Curie Temperature.[5] Above the Curie Temperature, the polymer exhibits paraelectric behavior, which does not allow for ferroelectric behavior because the electric fields do not align."