Highly methanol resistant and selective ternary blend membrane composed of sulfonated PVdF-co-HFP, sulfonated polyaniline and nafion

Partially sulfonated poly(vinylidene fluoride-co-hexafluoro propylene)/partially sulfonated polyaniline (SPVdF-co-HFP/SPAni) binary blend membranes have shown promising results in terms of low methanol permeability and high membrane selectivity compared to Nafion-117 membrane. However, the proton conductivity and IEC of this binary blend membrane was much lower than Nafion-117. It was found that incorporation of minimal quantity of Nafion within SPVdF-co-HFP/SPAni blend membrane at a constituent weight % ratio of SPVdF-co-HFP:SPAni:Nafion = 50:40:10 induced significant improvements in ion-exchange capacity (IEC), proton conductivity and tensile strength over that of the binary blend membrane. In addition, the SPVdF-co-HFP/SPAni/Nafion ternary blend membrane exhibited much lower methanol permeability, higher membrane and relative selectivities and comparable IEC to Nafion-117. In effect, presence of minimal quantity of Nafion induced significant positive attributes to the ternary blend membrane; and assisted in reaching a balance between material cost and properties.