Raman and dielectric spectra of electrospun graphene oxide (GO)/polyvinylidene difluoride (PVDF) fiber mats

The dielectric and polymorphic properties of PVDF electrospun fiber mats, with and without graphene oxide, have been investigated at room temperature using dielectric and Raman spectroscopies The dielectric properties, i.e. the real part & varepsilon;1 of permittivity, the imaginary part & varepsilon;2 of permittivity, the loss tangent tan delta and the ac electrical conductivity sigma ac, of the PVDF fiber mat and GO/PVDF fiber mat were analyzed as a function of frequency in the (103 divided by 106) Hz range using a LCR meter. The dielectric response of a PVDF film, obtained by applying 1.5 tons to a PVDF pellet, is also analyzed for comparison. The dielectric data well agree with the relative Raman spectra suggesting that the beta phase is dominant in both PVDF film and PVDF fiber mat. Instead, in the GO/PVDF fiber mat, the beta phase content decreases in favor of the alpha phase contrary to what is reported in the literature. The presence of well-defined D, G and 2D bands demonstrates that GO was successfully incorporated in PVDF fiber mat.