A simple, scalable method for fabricating fouling-resistant ultrafiltration membranes is described. A self-doped, sulfonated form of polyaniline was blended into polysulfone (PSf) ultrafiltration (UF) membranes to enhance hydrophilicity and fouling resistance. Polyaniline in its base form was sulfonated with fuming sulfuric acid, yielding sulfonated polyaniline (SPANi) with a degree of sulfonation of ∼0.5 confirmed by XPS. The SPANi polymer was dedoped and dissolved in a solution of polysulfone in N-methylpyrollidone at varying concentrations. During phase inversion to form membranes, SPANi is redoped and precipitated within the PSf membrane films in a facile one-step process. Composite membranes containing increasing amounts of SPANi were compared to the pure PSf membranes to determine changes in performance, hydrophilicity, and antifouling characteristics. The composite membranes exhibit fluxes similar to those of the pure PSf membrane and maintain rejection properties similar to those of current UF membranes. Captive bubble contact angle measurements and atomic force microscopy suggest increasing membrane hydrophilicity with increasing SPANi content. During flux decline and recovery experiments, SPANi/PSf composite membranes exhibited higher flux recovery than a pure PSf membrane, with the best performing membrane regaining 95% of its original flux after being washed with deionized water, demonstrating a high resistance to irreversible fouling.

Highly dispersible polypyrrole (PPy) nanospheres were synthesized and used to produce polysulfone (PSf) nanocomposite ultrafiltration membranes by a non-solvent induced phase separation (NIPS) process. The composite networks formed between PPy and PSf lead to higher porosity, hydrophilicity, surface charge, thermal stability, and water permeability, but slightly lower protein rejection. Nanocomposite membranes containing up to 20% PPy nanospheres were >10 times more permeable than pure PSf membranes, while the bovine serum albumin (BSA) rejection decreased from 94 to 82%.With nanoscale pores, high porosity, improved hydrophilicity, and tunable surface charge properties, the PPy/PSf nanocomposite membranes hold great promise for advanced protein separation, dialysis, water filtration and other macro molecular separations. Africa † Electronic supplementary information (ESI) available: Data for contrast adjusted surface SEM images, AFM images, and proposed geometric structure of the PPy/PSf nanocomposite membrane can be found in ESI. See

We present a method to produce anti-fouling reverse osmosis (RO) membranes that maintains the process and scalability of current RO membrane manufacturing. Utilizing perfluorophenyl azide (PFPA) photochemistry, commercial reverse osmosis membranes were dipped into an aqueous solution containing PFPA-terminated poly(ethyleneglycol) species and then exposed to ultraviolet light under ambient conditions, a process that can easily be adapted to a roll-to-roll process. Successful covalent modification of commercial reverse osmosis membranes was confirmed with attenuated total reflectance infrared spectroscopy and contact angle measurements. By employing X-ray photoelectron spectroscopy, it was determined that PFPAs undergo UV-generated nitrene addition and bind to the membrane through an aziridine linkage. After modification with the PFPA-PEG derivatives, the reverse osmosis membranes exhibit high fouling-resistance.