Novel nanocomposite membranes based on blended sulfonated poly(ether ether ketone)/poly(vinyl alcohol) containing sulfonated graphene oxide/Fe3O4 nanosheets for DMFC applications

Abstract

In this study, sulfonated graphene oxide (SGO)/Fe₃O₄ nanosheets were synthesized by hydrothermal method and incorporated into blend sulfonated poly(ether ether ketone) (SPEEK)/poly(vinyl alcohol) (PVA) matrix with different weight percent of (SGO)/Fe₃O₄ nanosheets. The performances of prepared membranes were investigated by water uptake, membrane swelling, mechanical and thermal stability, proton conductivity, methanol permeability and DMFC test. It was found that the water uptake and tensile strength of SPEEK membrane increased and proton conductivity and power density decreased by blending with PVA. Incorporation of SGO/Fe₃O₄ nanosheets into SPEEK/PVA matrix enhanced mechanical stability, proton conductivity and methanol barrier properties of membrane. The SPEEK/PVA/SGO/Fe₃O₄ nanocomposite membrane with optimal nanosheets content (5 wt%) exhibits low methanol permeability (8.83 × 10⁻⁷ cm² s⁻¹), high tensile strength (51.2 MPa), high proton conductivity (0.084 S cm⁻¹ at 25 °C) and high power density (122.7 mW cm⁻² at 80 °C) and suggests its potential application in DMFCs.