The effects of conductivity of the polymer on the dielectric and ferroelectric properties of the PLZT/P(VDF-co-TrFE) nanocomposites

The lead lanthanum zirconate titanate (PLZT) nanoscale particles with a cubic crystal cell and the favorable surface activity obtaining from sol-gel method are adopted as the filter. And a ferroelectric poly (vinylidene fluoride-co- trifluoroethylene) (P(VDF-co-TrFE)) copolymer synthesizing by an atom transfer radical polymerization (ATRP) process from commercial poly (vinylidene fluoride-co- chlorotrifluorethylene) (P(VDF-co-CTFE)) is selected as the polymer matrix to form the PLZT/P(VDF-co-TrFE) 0-3 nanocomposites. By expressing the influence of conductivity of polymer on the distribution of polarizing electric field on the ceramic particles and polymer matrix, we find that the relative high conductivity of the P(VDF-co-TrFE) may result in a high electrical field applying on the PLZT particles, which will further enhance the dielectric and ferroelectric properties of the composites. Consequently, for the combining contributions of ionic and dipole polarizations, the PLZT/P(VDF-co-TrFE) nanocomposite film with 20wt% PLZT possesses a very large dielectric constant of 85 at 100 Hz, a high ferroelectric property (Dm∼7.5 μC/cm2 and Dr∼5 μC/cm2) at a small polarizing electrical field of 37.5 MV/m, and an excellent piezoelectric constant of −31 pC/N after thermal polarizing under 5 MV/m at 100 °C, respectively. Considering their good mouldability, favorable ferroelectric and piezoelectric properties, the flexible PLZT/P(VDF-co-TrFE) film provides a reliable reference of the potential using of the ceramic/polymer nanocomposites in sensor, actuator, and other mechanical-electrical energy transforming devices.