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 ϵ1 of permittivity, the imaginary part ϵ2 of permittivity, the loss tangent tanδ and the ac electrical conductivity σac, of the PVDF fiber mat and GO/PVDF fiber mat were analyzed as a function of frequency in the (103 ÷ 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 β phase is dominant in both PVDF film and PVDF fiber mat. Instead, in the GO/PVDF fiber mat, the β phase content decreases in favor of the α 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.