The dielectric constant of fluorinated polymides, their blends, and composites is known to decrease with the increase in free volume due to a decrease in the number of polarizable groups per unit volume. Herein, we report an interesting finding on the origin of dielectric constant in a polymer blend prepared using a fluorine-containing polymer and a polyimide probed in terms of its available free volume, which is distinct from the generally observed behavior in fluorinated polyimides. For this study, a blend of poly(vinylidene fluoride-co-hexafluoro propylene) and poly(ether imide) was chosen and the interaction between them was studied using FTIR, XRD, TGA, and SEM. The blend was investigated by positron annihilation lifetime spectroscopy (PALS), Doppler broadening (DB), and dielectric analysis (DEA). With the increase in the free volume content in the blend, surprisingly, the dielectric constant also increases and is attributed to additional space available for the polarizable groups to orient themselves to the applied electric field. The results obtained would pave the way for more effective design of polymeric electrical charge storage devices.

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Barium titanate nanoparticles with an average size of <100 nm were added to poly(vinylidene fluoride‐trifluoroethylene) copolymer in varying concentrations (0.2, 0.4, 0.6, and 0.8 wt%) in liquid phase under bath sonication and annealed at 120°C for 2 h. The Fourier transform infrared spectroscopy, X‐ray diffraction, Raman spectroscopy, and Differential scanning calorimetry studies reveals an increase in the β‐phase content of the nanocomposite, which is a promising inference for the increased ferroelectric property of the material. Scanning electron microscopy and Atomic force microscopy was used to study the surface topography of the spin coated thin films. Polarization–electric field studies clearly indicating the enhanced ferroelectric nature of optimized concentration with highest remnant polarization. All these results nominate this polymer nanocomposite as a promising material for ferroelectric applications like nonvolatile memory devices. POLYM. COMPOS., 38:1655–1661, 2017. © 2015 Society of Plastics Engineers