Piezoelectric and pyroelectric properties of lead titanate-polyethylene oxide composites

Polymer-ceramic composites with pyroelectric sensitivity are presented as promising candidates for infrared detection. Selection of the appropriate ceramic filler and the polymer matrix is one of the key parameters in the development of optimized materials for specific applications. In this work lead-titanate (PT) ceramic is incorporated into a flexible polymer matrix, polyethylene oxide (PEO) with relatively high electrical conductivity to develop sensitive and at the same time flexible composites. PT particles are dispersed in PEO at varying volume fractions, and composite materials cast in the form of films for the measurements. The dielectric, piezoelectric and pyroelectric properties are measured. From these data the piezoelectric voltage coefficients as well as pyroelctric figures of merit of the composite films have been determined and values were compared with that of PT-epoxy composites in order to determine the effect of electrical conductivity of the polymer matrix on the poling efficiency and the final properties. It is found that, in general, both the piezoelectric and the pyroelectric figures of merit increase with concentration of PT; however, it is at the expense of mechanical flexibility of the material. Moreover PT-PEO composites show superior pyroelectric sensitivity compared to PT-Epoxy composites. Improving the electrical conductivity of the polymer phase enhances the poling process significantly.