Phase diagram of poly(VDF-ter-TrFE-ter-CTFE) copolymers: Relationship between crystalline structure and material properties

Depending on their CTFE content (from 0 to 10 mol %), poly(VDF-ter-TrFE-ter-CTFE), poly(vinylidene fluoride-ter-trifluoroethylene-ter-chlorotrifluoroethylene) copolymers, exhibit ferroelectric (FE) or relaxor (RFE) properties at room temperature. Solvent cast films of these terpolymers can crystallize in three orthorhombic phases: FE, DFE (Defective Ferroelectric) RFE according amount CTFE. The relative each crystalline phase depends the and evolves after annealing. We study dependence electric displacement?electric field (D?E) loop with annealing step. observed a closely link between remnant polarization, PR, fraction (FE + DFE) phase. Macroscopic properties, studied using thermo-mechanical experiments (DSC DMA) dielectric spectroscopy, evolve continuously are well correlated structural properties. Finally, temperature versus mol% diagram is established discussed relation-ship material