Ferroelectric Ceramic/Polymer Composite As Multifunctional Material

W. K. Sakamoto1, G. P. Estevam2, R. L. B. Freitas3, R. T. Higuti3, A. A. Carvalho3, J. A.

Malmonge1, A. Sanches1

1Faculdade de Engenharia – Unesp/Ilha Solteira – Depto. de Física e Química 2Fatec – Araçatuba – Depto de Biocombustíveis

3Faculdade de Engenharia – Unesp/Ilha Solteira – Depto de Engenharia Elétrica E-mail: sakamoto@dfq.feis.unesp.br

The continuous technological advances have required materials with properties that conventional material cannot display. In this context, multifunctional or smart materials have attracted much attention in scientific community in the last decade. Material property combinations are being the focus to the development of composite materials, which are considered a multiphase material that exhibits properties of the constituent phases. One interesting material to be studied as sensing material is the composite made of ferroelectric ceramic and polymeric matrix as a two phase composite material. In that case the combinations properties intended are the high piezo and pyroelectric activities of the dense ceramic with the impact resistant, flexibility, formability and low densities of the polymer. The composite studied here is made of a lead zirconate titanate (PZT) ceramic dispersed in a polymer matrix. Using the piezoelectric property the composite film was used to detect acoustic emission (a.e), which is a transient elastic wave generated by sudden deformation taken place in materials under stress. Acoustic emission can be applied for evaluating the “health” of structures in a non-destructive way. The composite film was surface mounted on an aluminum panel and ball bearing drop and pencil lead break were used as simulating a.e. sources. On the pyroelectric side, the composite film was used as sensing element in a pyroelectric chamber to measure ionizing and non-ionizing radiant energy, such as: x-ray intensity in the orthovoltage range (120 kVp – 300 kVp) and infrared radiation. Experimental results indicate that the combination properties of ceramic and polymer phases provide an alternative sensing material to be used as piezo and pyroelectric sensor. Furthermore, in the present work was demonstrated that the composite can be used for energy harvesting.

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Acknowledgement – Thanks are due to fapesp and cnpq for the financial support.

Fig. Power generated as a function of time during sample deformation.