Why ferroelectric polyvinylidene fluoride is special

Ferroelectric polymers entail a number of constraints, which together limit the useful compositional variations. These constraints include the following: a stable molecular dipole moment, compact crystal structure, conformational flexibility, and minimal steric hindrance. They are well satisfied by the prototype ferroelectric polymer, polyvinylidene fluoride, and yet almost every other conceivable molecular structure is limited by comparison.