Integration and characterization of a ferroelectric polymer PVDF-TrFE into the grain boundary structure of ZnO via cold sintering

In this study, the Cold Sintering Process (CSP) is used to design ceramic-polymer composites with Polyvinylidene fluoride Trifluoroethylene (PVDF-TrFE), a ferroelectric co-polymer, as an active intergranular grain boundary phase in a semiconducting Zinc Oxide (ZnO) electroceramic matrix. The conductivity is modeled with Schottky thermionic emission and Fowler-Nordheim tunneling as a function of both temperature and voltage. In addition, through details of the dielectric characterization, the interfaces are also considered with the effective permittivity resulting with a space charge relaxation of the PVDF-TrFE. The Maxwell-Wagner-Sillars (MWS) model was used to predict ~ 3 nm as the thickness of the intergranular PVDF-TrFE phase controlling electrical properties of the composite. Transmission electron microscopy (TEM) investigation of the grain boundary phase confirms the polymer thicknesses to the dimensions predicted from the various electric measurements and subsequent modeling.