Dielectric and pyroelectric response of PVDF loaded with BaTiO3 obtained by mechano synthesis

Electroactive composites based on ferroelectric ceramic and polymer components are still of interest since their properties can be easily tailored to the requirements of smart structures, sensors and actuators. We studied the dielectric and pyroelectric response of poly(vinylidene fluoride) loaded with BaTiO3 nanograins obtained by mechanically activated synthesis from BaO and TiO2. The BaTiO3 nanopowder was characterized by X-ray diffraction, transmission electron microscopy and NIR Raman scattering. The relaxation processes in the polymer matrix were found to determine the dielectric response of the composites but with higher permittivity values due to the presence of BaTiO3. The activation energy of the segmental motion of the polymer matrix was found to increase with increasing contents of the filler. The dielectric response of the composites with volumetric fraction of BaTiO3 equal to and greater than 0.24 was found to be dominated by a broad maximum at similar to 320 K, which we relate to the Curie point of the ferroelectric nanograins. (c) 2007 Elsevier B.V. All rights reserved.