Probing the local interactions and their effects on the dielectric properties of PVDF/PVP composite films

Composite films of poly(vinylidene fluoride)/poly(vinylpyrrolidone) (PVDF/PVP) were studied for their morphology, microstructure and vibrational properties. The influence of PVP as an additive on the chemical structure of the host matrix was explored through Raman, Fourier-transform infrared (FTIR) and X-ray absorption spectroscopy (XAS) studies. The fraction of the electroactive phase was found to decrease to ∼26% with respect to that in the pristine PVDF films with an additive concentration of ∼ 6 wt%. The dielectric constant of the films was also found to enhance significantly (by almost two times). X-ray absorption studies showed an increase in the absorption intensity at the K-edge spectra of C1s, F1s, O1s and N1s with the addition of PVP. Furthermore, the interaction between the carbonyl group (C=O) of PVP and the methylene group (-CH2-) of PVDF results in the reduction of the dielectric loss of the composite films.