Numerically Determining Material Coefficients of Micro-Injection Molded PVDF/PZT Piezoelectric Composites With Controlled Filler Orientation

Abstract

In the present work, novelly structured poly(vinylidene fluoride)/lead zirconate titanate (PVDF/PZT) piezoelectric composites with controlled filler orientation were designed. The material coefficients of the proposed composites including elastic stiffness constant (C), piezoelectric constant (e) and dielectric constant (ε) were numerically determined. Specifically, the Comsol Multiphysics connected with Matlab was utilized to create the unit cells representing the piezoelectric composites. In the calculations, the whisker-shaped PZT content was varied in a relatively low range of volume fraction (i.e., 0.3∼3.5 vol.%). Furthermore, the PZT orientation and PZT length-reduction were considered in order to simulate the flow-field effect of micro-injection molding (μIM). The results showed that using a low PZT content was effective for modifying the composite’s material coefficients. In addition, the PZT orientation was identified as an important factor influencing the composite’s properties, which was believed to result from the apparently changed amount of the PZT whiskers along the direction of interest. Finally, the effect of the PZT length-reduction during μIM was found insignificant, which suggests that μIM can be safely adopted to fabricate PVDF/PZT piezoelectric composites taking full use of its advantages such as high efficiency and low cost, without worrying about PZT’s length-reduction.