Fabrication of high proton conducting composite membranes from amino group functionalized MOF and semi-fluorinated sulfonated poly(arylene ether sulfone)s

A series of polymer-metal–organic frameworks (MOF) hybrid composite membranes have been prepared with an amino group functionalized MOF (Cu-SAT) and phthalimidine-based aromatic fluorinated sulfonated poly(arylene ether sulfone)s (PAQSH-XX). The MOF was incorporated within the polymer matrix by solution blending method and a series with membranes having 10 wt% of the MOF in PAQSH-XX of varied DS (degree of sulfonation) was prepared. The acid form of the membranes was successfully obtained by treating them with sulfuric acid. The properties of these hybrid membranes PAQSH-XX/ Cu-MOF (XX = 30 to 60) were studied and compared to that of the corresponding pristine PAQSH membranes. The copolymer and the hybrid membranes were characterized using FT-IR and thermal analysis. The membranes showed high solubility in all commonly used solvents. The uniform dispersion of the MOF within the polymer matrix was observed from scanning electron microscopy (SEM). Atomic force microscopy (AFM) images of the membranes showed well-separated phases which were confirmed by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The membranes also showed desirable improvements in the proton conductivities, water uptake, and swelling without affecting the oxidative stability values.