Synthesis of PVDF/BiFeO3 nanocomposite and observation of enhanced electrical conductivity and low-loss dielectric permittivity at percolation threshold

A novel two‐phase polymer nanocomposite film comprising of polyvinylidene fluoride (PVDF) and nanocrystalline (∼90 nm) semiconducting multiferroic BiFeO3 (BFO) have been fabricated by hot‐molding technique. Such flexible thick nanocomposite films, semicrystalline in nature, exhibited extraordinarily high effective dielectric permittivity εeff ∼ 103 (compared with that of pure PVDF) near the low percolation threshold (fc = 0.12) at room temperature (RT) and the films also possessed low dielectric loss (∼0.18). The polarization‐electric field (P‐E) hysteresis loops are displayed at RT, which indicate ferroelectric like behavior of PVDF still persists in the percolative nanocomposite. There is also large increase of remanent polarization of BFO in the composite indicating improvement of the multiferroic behavior of BFO embedded in the PVDF polymer. The sample also indicates good fatigue endurance. Formation of microcapacitors and percolative behavior are correlated to explain the obtained results based on the special geometry of the BFO nanofillers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 Multiferroic polymer composite films consisting of an insulating polymer host (PVDF) and multiferroic BiFeO3 nanoparticles are promising device grade materials for smart capacitor applications requiring high dielectric permittivity and low loss. A flexible, two‐phase polymer nanocomposite thick film was designed using simple hot molding, and the dielectric and ferroelectric properties of these composite were investigated. The composite possessed extraordinarily high dielectric permittivity (∼103) and low dielectric loss (∼0.18) at the percolation threshold (fc = 0.12) and good ferroelectric character.