Behaviour of multiphase PVDF in (1−x)PVDF/(x)BaTiO3 nanocomposite films: structural, optical, dielectric and ferroelectric properties

The present paper deals with the synthesis and characterization of (1−x)PVDF/(x)BaTiO3 nanocomposite films with x = 0.1, 0.2, 0.3, 0.4 and 0.5. The samples were synthesized by simple solution mixing method followed by tape casting process. FESEM images show the homogeneous dispersion of BaTiO3 nanoparticles within the matrix of poly(vinylidene fluoride) (PVDF) with slight agglomeration. An improvement in the thermal stability of nanocomposite film is observed by TGA results. XRD as well as FTIR analysis indicate the α–β phase transition of PVDF in the nanocomposite films. The embedded BaTiO3 forms an intermediate band among the PVDF structures and thus decreases the band gap of nanocomposite films by absorbing the wavelength of lower energies. The band gap of nanocomposite films for x = 0.4 decreases to 2.4 eV as compared to 5.0 eV for pristine PVDF. The dielectric constant (ɛ′) of pristine PVDF at 50 Hz is 8.9, which increases to 26.7 for (0.6)PVDF/(0.4)BaTiO3 nanocomposite film. An increase in the charge storage ability is observed from PE loops, as (0.6)PVDF/(0.4)BaTiO3 nanocomposite film has highest value of polarization (0.093 µC cm−2) as compared to pristine PVDF (0.020 µC cm−2). This shows an increase in the charge storage ability of (1−x)PVDF/(x)BaTiO3 nanocomposite films as compared to pristine PVDF.