Smart materials, which exhibit piezoelectricity, find an eclectic range of applications in the industry. The direct piezoelectric effect has been widely used in sensor design, and the inverse piezoelectric effect has been applied in actuator design. Ever since 1954, PZT and BaTiO 3 were widely used for sensor and actuator applications despite their toxicity, brittleness, inflexibility, etc. With the discovery of PVDF in 1969, followed by development of copolymers, a flexible, easy to process, nontoxic, high density alternate with high piezoelectric voltage coefficient was available. In the past 20 years, heterostructural materials like polymer ceramic composites, have received lot of attention, since these materials combine the excellent pyroelectric and piezoelectric properties of ceramics with the flexibility, processing facility, and strength of the polymers resulting in relatively high dielectric permittivity and breakdown strength, which are not attainable in a single phase piezoelectric material. The current review article is an attempt to provide a compendium of all the work carried out with reference to PVDF-PZT composites. The review article evaluates the effect of grain size, content and other factors under the purview of dielectric and piezoelectric properties while evaluating the sensitivity of the material for sensor application. POLYM. ENG. SCI., 55:1589-1616, 2015

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Piezoelectric polymer-ceramic composite materials are promising candidate for transducer application because of their inherent capability of combining the favourable properties of both ceramic and polymer materials. Present work discusses the dielectric properties of such composite films developed from two piezoelectric materials viz. Poly(vinylidene fluoride) (PVDF) as a matrix and Lead Zirconate Titanate (PZT) as filler in PVDF. PVDF-PZT composite films were prepared by solvent casting method followed by hot pressing for better packing and connectivity of ceramic phase in the composite and hence improved piezoelectric properties in the material. The dielectric parameters of these films are evaluated by the measurement of dielectric constants (ε and ε), intrinsic impedance, capacitance and dielectric loss, etc. as function of frequency at room temperature. The temperature dependence of the dielectric properties is studied as well from 40˚C to 75˚C. It was found that dielectric properties like permittivity and capacitance were quite stable in the frequency range 100 Hz-100 kHz. A variation of 20 to 50% in dielectric properties was observed, for increase in temperature with respect to room temperature, which may be accounted to pyroelectric behaviour of material.