Enhanced Dielectric Constant of PVDF-HFP/BFO Composite Films for Ferroelectric Applications

We have developed multiferroic Bismuth ferrite (BiFeO3, BFO) incorporated Poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer-ceramic composites through solution casting method. The polymer-ceramic composites are fabricated by varying the composition of the BFO as a filler material ranging 5, 10, 15, 20, 25, 30, and 40 wt% into the PVDF-HFP polymer matrix. We have investigated the effect of BFO loading on the structural, morphological, spectroscopic, and dielectric properties by different characterization techniques. X-ray diffraction analysis indicates the presence of non-polar α- and polar β- phases of PVDF-HFP in the composites. Scanning electron microscope studies revealed the spherulite morphology and homogenous dispersion of BFO particles. The addition of BFO filler in PVDF-HFP matrix at various percentages has been studied to improve the polar -phase of PVDF-HFP which may enhance ferroelectric properties. The dielectric studies at room temperature showed an increase in dielectric constant value from 9.5 (pure PVDF-HFP) to 21.08 (30% loaded BFO) at 100Hz. It is also evident from the Fourier Transform- Infrared (FT-IR) spectra, that a maximum of 75.24% of β-fraction is observed for 30% loaded BFO composition. The enhanced properties of the fabricated materials suggest that they may be useful for polymer-ceramic capacitor applications. The results are discussed in detail.