Enhanced polarization in zirconia-P(VDF-TrFE) laminar composite dielectrics

Zirconia-P(VDF-TrFE) double-layered laminar composites are experimentally investigated to understand inorganic-organic interfacial effects in composite dielectrics. The DC and AC electrical response of the individual phases were characterized in addition to the zirconia-P(VDF-TrFE) composite. The measured real part of permittivity for the laminar composite is found to be higher than theoretically calculated values using series mixing rules for zirconia and P(VDF-TrFE). Additional polarization of the composite structure can be attributed to either the presence of interfacial polarization of zirconia and P(VDF-TrFE) or modification of polymer. Impedance spectroscopy has shown that dielectric properties of laminar composites are dominated by zirconia thin films in low frequency region. The impedance spectroscopy shows that zirconia blocks charge carrier motion and hence partially contribute towards additional interfacial polarization in the laminar composite. The dielectric response of the laminar composite was also modeled through a Maxwell-Wagner interfacial polarization mechanism, which was found to inadequately describe the polarization response. Equivalent circuit modeling of the composite has revealed an additional interfacial circuit element for the additional polarization, suggesting a structurally modified polymer at the interface.