Structural Tailing and Pyroelectric Energy Harvesting of P(VDF-TrFE) and P(VDF-TrFE-CTFE) Ferroelectric Polymer Blends

The copolymer P(VDF-TrFE) is a normal ferroelectric because the bulky TrFE monomer improves its crystalline chain structure, while the terpolymer P(VDF-TrFE-CTFE) is a relaxor ferroelectric because the third monomer CTFE makes it amorphous. Herein, in order to induce a crystalline beta phase in the terpolymer, we blended a small amount of crystalline P(VDF-TrFE) into P(VDF-TrFE-CTFE) and investigated the effect of blending on the pyroelectric energy harvesting (PyEH) properties. The polarization-electric field hysteresis loops at different temperatures and energy densities were investigated. The PyEH energy density (ND) is compared with the electrical energy density (UE). The UE and ND at the ferroelectric–paraelectric transition temperature for the χ = 0.1 blend are reported as 3.18 and 5.04 J/cm3, respectively, which are higher than the other polymer blends. Interestingly, the ND of the χ = 0.9 blend is found to be 3.44 J/cm3 when operated at lower and higher temperatures, that is, at TL = 25 °C and TH = 40 °C, respectively, which is the highest possible energy density at the lowest possible transition temperature for the polymer blends.