Enhanced dielectric and ferroelectric properties of surface hydroxylated Na0.5Bi0.5TiO3 (NBT)-poly(vinylidene fluoride) (PVDF) composites

The surface hydroxylation treatment has been carried out by using hydrogen peroxide (H2O2) to modify the surface of Na0.5Bi0.5TiO3 (NBT) particles in a ferroelectric polymer (PVDF) via solution casting technique. The FTIR study confirms the presence of hydroxyl groups on the surface of NBT. The FE-SEM analysis reveals that h-NBT particles are dispersed homogeneously within the polymer matrix. The surface hydroxylation treatment plays an important role in high dielectric constant and also reduced loss by conducting the material surface with -OH functional groups. The prepared composite with 40 wt.% of h-NBT showed enhanced dielectric constant (approximate to 114), negligible loss (0.22) and high AC conductivity as compared to that of the unmodified NBT. Such significant enhancement in dielectric properties may be due to the strong interaction between h-NBT particles and PVDF matrix at the interface. The percolation theory is used to explain the dielectric properties of h-NBT-PVDF composite. Furthermore, the remnant polarization of the un-poled h-NBT-PVDF composites (2 Pr-1.19 mu C/cm(2) for 40 wt.% of h-NBT) is also improved. The present findings give an idea of high dielectric constant and relatively low loss composite materials as a promising candidate for electronic and energy storage devices.