On the mechanisms of DC conduction in electrospun PLZT/PVDF nanocomposite membranes

Designing dielectric nanocomposite films with excellent dielectric properties is of strategic importance for a variety of applications requiring pressure sensing, energy harvesting and storing, and biomedical technology. Hence, the present investigation aims at studying the dielectric properties of lead lanthanum zirconate titanate (PLZT)/poly(vinylidene fluoride) (PVDF) nanocomposite based membranes fabricated using traditional electrospinning techniques. The composites were investigated for structural and electrical conductivity properties at varying temperatures. While the Scanning Electron microscope revealed beaded and unannealed micro/nanofibers, the observations of temperature-dependent electrical conductivity imply that the charge carrier transport phenomena involve more than one conduction mechanism. This is an interesting observation and can be explained in terms of the contents and porosity of the composites. As compared to PVDF, PLZT/PVDF nanocomposite films have somewhat better conductivity. The space charge limited current was the dominant mechanism at high voltages, while the Schottky–Richardson conduction mechanism was dominating at high temperature, according to observed J–V characteristics. The DC activation energy was found to be different, as expected, due to the dynamically heterogeneous nature of PLZT aggregates within the polymer matrix; however, the films exhibit the well-known Arrhenius relationship. This indicates that the dominant conduction mechanism is observed to be electronic and thermally activated. Graphical abstract: [Figure not available: see fulltext.]