Piezoelectric property of PVDF/graphene composite films using 1H, 1H, 2H, 2H-Perfluorooctyltriethoxysilane as a modifying agent

Abstract

A novel modifier, 1H, 1H, 2H, 2H-Perfluorooctyltriethoxysilane (PFOES), was introduced for the covalent functionalization of graphene for the first time. TEM, XPS, FT-IR, Raman, AFM and TGA were employed to characterize the morphology and structure of the PFOES-rGO. Furthermore, PVDF/PFOES-rGO composite films with different PFOES-rGO loadings were prepared by solution mixing. The dispersion of such PFOES-rGO containing fluorine ended-groups in PVDF was effectively improved compared to graphene as SEM showed. Thus, the PFOES-rGO could nucleate the PVDF crystallization and induce the formation of nearly all β phase. The dielectric, piezoelectric and dynamic mechanical properties of the PVDF/PFOES-rGO composite films were then comprehensively studied. The dielectric (at 1 kHz) and the piezoelectric constants of the PVDF/PFOES-rGO composite film at 0.3 wt% PFOES-rGO compared with the neat PVDF was greatly improved by 370% and 80.9%, respectively. The PFOES-rGO also greatly enhanced the mechanical property of PVDF composites. It is proved the modification method for graphene used in this study is very effective.