Dielectric properties and spatial distribution of polarization of ceramic plus polymer composite sensors

Thin films ceramic + polymer composite sensors with mixed connectivities possess high values of piezo- and pyroelectric coefficients and the formability and flexibility which are not attainable in a single-phase ferroelectric material, i. e., an electroceramic or a polymer. The efficiency and the piezo- and pyroelectric figure of merit (FOM) are influenced by the temperature dependence of the dielectric properties and the nature of the spatial distribution of polarization of the composite material. We report the results of a study of dielectric properties of calcium - modified lead titanate (PTCa) and a polar copolymer, polyvinylidene fluoride and trifluoroethylene P(VDF-TrFE) and PTCa and epoxy in a wide frequency range. Each of the two composites was fabricated with two different volume fractions of the constituent phases. Furthermore, the spatial distribution of polarization was determined by the laser intensity modulation method (LIMM) for each composite sensor in order to assess the polarization distribution of the sensors. These results are also reported in this work.