Dynamic dielectric response of PLZT-P(VDF/TFE) nanocomposites

Abstract

Dynamic dielectric relaxation of polymer P(VDF/TFE)(0.98/0.02) loaded with lead lanthanum zirconate titanate (Pb0.92La0.08)(Zr0.65Ti0.35)O3(PLZT 8/65/35) ceramic nanopowders was studied in the frequency range from 100 Hz to 1 MHz and at temperatures from 100 K to 450 K. The PLZT nanopowders were prepared by the sol-gel method using: lead(II)acetate trihydrate, lanthanum acetate hydrate, zirconium(IV)propoxide and titanium(IV)propoxide. The crystallization process of PLZT powders was monitored by means of XRD analysis (Philips PW 3710) using Cu-Kα radiation in the range 20° ≤ 2Θ ≤ 60°. The powders were analyzed before and after burning of the organic remains. The morphology observations of the powders were made using Hitachi S-4700 scanning electron microscope (SEM), and the grain size distributions were measured on a Zetasizer Nano ZS by the DLS method. The PLZT-P(VDF/TFE) composite samples of 0-3 connectivity were prepared from ceramic and polymer powders by the hot-pressing method. The volume fraction of the ceramics Θ amounted 0.1, 0.15 and 0.2. The dielectric response of the ceramics-polymer composite was found as a combination of the responses of pure polymer and the ceramics: (i) the addition of the PLZT ceramics increases the value of the dielectric permittivity ϵ, (ii) the composite shows the maximum of the permittivity coming from the PLZT ceramics, (iii) the dielectric absorption spectrum of the composites is dominated by the α-relaxation in pure polymer.