Piezoelectric and pyroelectric properties of PZT/P(VDF-TrFE) composites with constituent phases poled in parallel or antiparallel directions

Abstract

Composites of lead zirconate titanate (PZT) powder dispersed in a vinylidene fluoride-trifluoroethylene copolymer [P(VDF-TrFE)] matrix have been prepared by compression molding. Three groups of polarized samples have been prepared by poling: only the ceramic phase, the ceramic and polymer phases in parallel directions, and the two phases in antiparallel directions. The measured permittivities of the unpoled composites are consistent with the predictions of the Bruggeman model. The changes in the pyroelectric and piezoelectric coefficients of the poled composites with increasing ceramic volume fraction can be described by modified linear mixture rules. When the ceramic and copolymer phases are poled in the same direction, their pyroelectric activities reinforce while their piezoelectric activities partially cancel. However, when the ceramic and copolymer phases are poled in opposite directions, their piezoelectric activities reinforce while their pyroelectric activities partially cancel.

Phenomenological model for predicting thermoelectromechanical response of 2-2 piezocomposite

“…Kar-Gupta and Venkatesh 35 developed a model that takes into account the anisotropy of the fibers to study the behavior of piezocomposite where both phases are active. As highlighted by Chan, Ng and Choy 27,28 in the case of two-active-phase composites, the resulting piezoelectric coefficients can be enhanced if the phases exhibit opposite polarization. Such a configuration would have a considerable impact on the effective piezoelectric effects, rising the interest of a study under such circumstances.…”

Homogenized electromechanical coefficients and effective parameters of 1–3 piezocomposites for ultrasound imaging transducers

“…Kar-Gupta and Venkatesh [25] develop a model that takes into account the anisotropy of the fibres always to study the behaviour of piezocomposite where both phases are active. As highlighted by Chan, Ng and Choy [19,20] in the case of two-active-phase composites, the resulting piezoelectric coefficients can be enhanced if the phases exhibit opposite polarization. Such a configuration would have a considerable impact on the effective piezoelectric effects, rising the interest of a study under such circumstances.…”

“…Banno [16] formulates an analytical model to study the coupling of closed and open pore ceramics based on the modified cube model. In order to better understand the reality described by the experiments referring to the works mentioned above under different volumetric fractions, please consult the works of Furukawa et al [17], Steinhausen et al [18], Chan et al [19,20]. The model of Dunn and Taya [21] makes it possible to predict the behaviour of piezocomposite by evaluating its electromechanical properties using Mori-Tanaka's microdiffer-ential theories and the principle of dilute micromechanics.…”

Piezoelectric properties of PVDF‐TrFE/BaTiO3 composite foams with different contents of TrFE units

“…Similar results implying this negative impact of ceramic filler were reported by several authors. 45,46 The two-step polarization method adopted for the PVDF-TrFE(30) composite foams led to a different result. As observable in Figure 8, the higher the content of BaTiO 3 , the higher the absolute value of the d 33 of the PVDF-TrFE(30) composite foams (up to À28.3 pC N À1 in the case of 20 wt% of BaTiO 3 ).…”