Piezoelectric and electrostrictive

Piezoelectric and Electrostrictive Device Applications. Devices made from ferroelectric materials utilizing their piezoelectric or electrostrictive properties range from gas igniters to ultrasonic cleaners (or welders) (72). 

III. Methods for Measuring the Piezoelectricity and Electrostriction Constant of Polymer Films 3.1. Measurement of the Piezoelectric Constant... 

Oshiki,M., Fukada,E. The inverse piezoelectricity and electrostriction in elongated and polarized films erf polyfvinylidene fluoride). Rep. Progr. Polymer Phys. Japan 14, 471 (1971). 

Roy SS, Lehmann W, Gebhard E, Tolksdorf C, Zentel R, Kremer F (2002) Inverse piezoelectric and electrostrictive response in freely suspended FLC elastomer film as detected by interferometric measurements. Molec Cryst Liq Cryst 375 253... 

Piezoelectric and electrostrictive devices have become key components in smart actuator systems such as precision positioners, miniature ultrasonic motors and adaptive mechanical dampers. This section reviews the developments of piezoelectric and related ceramic actuators with particular focus on the improvement of actuator materials, device designs and applications of the actuators. 

Piezoelectric and electrostrictive materials are materials having the abihty to convert electric energy into mechanical energy. The effect is called piezoelectric if the generated surface charge density is linearly proportional to the... 

Figure 16.1 Schematic view of strain response in piezoelectric and electrostrictive polymers. When a small AC electric field superimposed on a DC bias field is applied on an electrostrictive polymer, an apparent piezoelectric response is observed.

The temperature has a very complicated influence on the E-M performance of polymers. The Young s modulus of polymer decreases with the temperature, but the temperature dependence of its dielectric properties can be very different. For some of the piezoelectric and electrostrictive polymers, there is a phase transition at temperatures close to room temperature. At the phase transition temperature, the dielectric permittivity reaches its maximum and the polymer exhibits a high dielectric loss. Additionally, at temperatures around the glass transition temperature, all polymers exhibit some dielectric relaxation and elastic relaxation, resulting in a frequency dependence of material properties and a high dielectric and elastic loss. 

If all the coefficients of equation (2) are known, one can accurately predict the longitudinal strain under a varying electric field for a given piezoelectric or electrostrictive material, and even for a material exhibiting both piezoelectric and electrostrictive effects, such as irreversible electrostrictive materials. For ideal reversible electrostrictive materials, which possess no remnant polarization at zero electric field, the odd power term of the electric field in equation (2) vanishes. However, we will consider the relaxor PLZT ceramics studied in this chapter as irreversible electrostrictives, to account for any ferroelectric behaviour under dc bias fields, and we will therefore include both terms of the electric field in equation (2). 

In this chapter, fundamental aspects of piezoelectricity and electrostriction in dielectric materials and especially in polymers will be outlined. In order to make the introduction into the subject easier to access, basic and schematic ways of describing the complex matter have been chosen instead of an elaborate or comprehensive theoretical approach. For more detailed and more precise information, the interested reader is referred to the large volume of available original and review hterature and to other relevant ehapters of this book. 

In die late nineteenth century, scientists quickly adopted flie seminal publications of the Curie brothers. Consequently, piezoelectricity and electrostriction were first discovered and investigated on inorganic, mono- or polycrystalline materials (Katzir 2006). Therefore, the theoretical treatment of tire relevant electromechanical properties has been based on the physics and in particular on the structure and the anisotropy of crystals (Newnham 2005 Tichy et al. 2010). Semicrystalline or amorphous polymers are usually less anisotropic flian crystals, and the symmetry... 

NonUnearities play essential roles not only in the poling of electrets and ferroeleciric materials (hysteresis, etc.) but also in their piezoelectric and electrostrictive behavior. In addition, piezoelectricity and electrostriction also lead to nonlinearities in the dielectric response of the respective materials (for a general introduction, see Richert (2010)). Consequently, the pressure dependence and the nonlinearities of the dielectric response have been foci of attention in the area of piezoelectricity and electrostriction in inorganic (Zhang et al. 1988) and polymeric (Furukawa et al. 1987 Bauer et al. 2005) dielectrics. Nonlinear effects are also particularly important at large electric fields or deformations (see, e.g., the recent review on the deformation of soft dielectrics (Zhao and Wang 2014) and refs, therein). 

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