Piezoelectric Polymer and Ceramic Ultrafine Fibers for Piezocomposite Films

This paper describes the process development and characterization of Poly(vinylidene fluoride) (PVDF) films and fiber mats and Zinc Oxide (ZnO) fibers as ingredients of a future piezo-composite film. The polymer system PVDF is electroactive and processed here by solution casting and annealing to form active films. Electrospinning of PVDF and Poly(vinyl alcohol)-Zincacetate precursor solutions were also under investigation to produce randomly oriented polymer and ceramic fiber mats, respectively. Effects of the electrospinning process and material parameters in the production of fiber mats were first studied by using Design of Experiments approach. Films produced by solution casting and fine fiber mats produced by electrospinning of PVDF were characterized regarding the manufacturability and distinct crystallization phases that determines the piezoelectric capability. The electrospun PVDF fibers as received indicated the insitu stretching effect that enables the required β-phase crystalline structure for piezoelectricity. The process flow for ZnO fibers that includes electrospinning of PVA-Zincacetate precursor fibers and calcinations was also investigated. Aside from typical fiber-like ZnO mats, ZnO whiskers and rods were also formed in this process flow.