Effect Of Dielectrophoretic Structuring On Dielectric And Piezoelectric Behaviors Of Zno/Pdms Microcomposite

It is well know that ZnO based polymer composite attract enormous research interests, especially in applications of sensor/actuator devices as well as energy harvesting systems. In this study, a PDMS polymer filled with ZnO microparticles were synthesized and its piezoelectric behavior was observed while varying the ZnO concentration, the dielectrophoretic alignment process, and the poling condition. A real-time observation of particles movement under an alternating (AC) field was achieved in non-cured composites through a digital microscopy. Several processing parameters including amplitude and frequency of the applied electric field was investigated to determine the best configuration of dielectrophoretic manipulation. Simulation and experiment results revealed that the alignment process of the particles improved the poling effect caused by the directionality of the network structures. Owing to the high ZnO/ZnO connectivity, the aligned composites give raise to significantly enhanced dielectric and piezoelectric properties with respect to those randomly dispersed. The dielectric permittivity and piezoelectric response of composites increase with an increasing ZnO volume fraction as well. Finally, a 2D finite element model (FEM) was developed to predict the dielectric constant and the piezoelectric coefficient of the ZnO material. Simulation was in good agreement with the experiment results, confirming that a well-designed network structure of the composite would be a viable approach to improve the piezoelectric performance.