Enhanced β Crystalline Phase in Poly(vinylidene fluoride) via the Incorporation of Graphene Oxide Sheets assisted by Supercritical CO2 Treatment

Abstract

ABSTRACTGraphene oxide (GO) sheets were pre-modified with a typical piezoelectric polymer, poly(vinylidene fluoride) (PVDF), using a simple supercritical carbon dioxide (SC CO2) method, and then the PVDF-decorated GO was added into a PVDF matrix by solution blending. Transmission electron microscopy (TEM) revealed that the decorating degree of PVDF on the surface of the GO increased significantly with increasing of SC CO2 pressure and PVDF concentration. The mechanism of the polymer adsorption on the GO sheets through favorable interaction between the GO and PVDF chains was identified via Fourier transform infrared spectroscopy (FTIR). Further, the crystallization behavior of PVDF/GO composites was investigated by differential scanning calorimetry (DSC), FTIR and polarized optical microscopy (POM). Interestingly, the composite with PVDF-decorated GO as the filler showed higher β-phase content compared to the composite with pristine GO as the filler. The study showed that the supercritical fluid-induced epitaxial crystallization process has significant potential for fabricating functional GO-based nanocomposties containing piezoelectric or conducting materials.