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Sulfonated poly(1,4-phenylene ether ether sulfone) (SPEES)/poly(ether imide) (PEI)/sulfonated graphene oxide (SGO) based proton exchange membranes (PEMs) were prepared by a solution casting method.

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Polyethersulfone (PES) was sulfonated by chlorosulfonic acid and concentrated sulfuric acid. The pure sulfonated PES (SPES) and modified SPES membranes were prepared by blending with different charged surface modifying macromolecules (cSMMs) namely, SPES/DEG‐HBS, SPES/PEG‐HBS, and SPES/PPG‐HBS. Membranes were characterized for their morphology, physical properties, and electrochemical properties in order to evaluate these membranes as cation exchange membranes. The blended membranes showed an increase in hydrophilicity, water uptake, and proton conductivity compared to the pure SPES membranes. The highest values of water uptake and proton conductivity were obtained for the SPES/PPG‐HBS blended membrane. Morphological studies revealed that the nodule size and surface roughness also influenced the water uptake, apart from the additional –SO3H group. Among the modified membranes, the SPES/DEG‐HBS blended membrane exhibited a lower methanol permeability value of 8.895 × 10−8 cm2 s−1 than the corresponding SPES membrane. The other two cSMM blended membranes showed higher methanol permeability values than SPES but still a smaller value than Nafion 117. The highest selectivity ratio (i.e., ratio of proton conductivity to methanol permeability) was obtained with the SPES/DEG‐HBS cSMM blended membrane. These results showed that the SPES/cSMM blended membranes have promise for possible use as a cation exchange membrane in fuel cells and electrolyzer applications.

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In this study, polyetherimide (PEI) ultrafiltration (UF) membranes were fabricated by incorporating different amounts of hydrophilic polyvinylpyrrolidone (PVP) via the phase inversion technique. The PEI/PVP blended membrane showed the highest pure water flux (147.1 L m–2 h–1), water content (70.2%), and surface energy (112.1 mN/m) when the 8 wt % of PVP was blended into the base polymer PEI. This particular membrane, designated as PVP 8, also showed the lowest contact angle (56.1°), hydraulic resistance (2.2 kPa/(L m–2 h–1)), and shrinkage ratio (4.3%). The addition of PVP has reduced the tensile strength of the PEI membrane because of the decrease in rigidity. The UF experiments with the following proteins, bovine serum albumin (BSA), egg albumin (EA), pepsin, and trypsin, had experienced a decrease in protein rejection whereas permeate flux increased by increasing PVP loading. The BSA adsorption experiment revealed that the adsorbed amount of BSA on the surface of the membrane was notably decreased from 0.17 mg cm–2 of neat PEI membrane to 0.08 mg cm–2 of PVP 8. The flux recovery ratio (FRR) experiment also showed that the fouling resistance property of the membrane was enhanced with the increment of PVP.