Tethering methoxy polyethylene glycols to improve the antifouling property of PSF/PAA‐blended membranes

Poly(acrylic acid) (PAA) was used as an additive to fabricate blended polysulfone (PSF) ultrafiltration (UF) membranes. Hexanediamine was used as a crosslinking agent to react with PAA and formed an active surface with amine group. Then, an end carboxyl group methoxy polyethylene glycol (MPEG) was grafted on the membrane surface via an amidation reaction. Water contact angle measurement indicated that the surface hydrophilicity of PSF/PAA‐blended membranes and MPEG‐modified membranes remarkably increased. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FTIR) was used to confirm the existence of PAA in the blended membranes and the change of chemical composition. Membrane surface and cross‐sectional morphologies were observed by scanning electron microscope. The flux of pure water increased slightly after modification, while the rejection to bovine serum albumin had no obvious change. The improvement of antifouling property for MPEG‐modified membrane was accordant with the increase of PAA content in PSF/PAA‐blended membranes. Protein UF experiments revealed that membrane fouling, especially irreversible membrane fouling, was remarkably reduced due to the incorporation of MPEG. The long‐term protein UF experiment demonstrated the improvement of recycling property and the reliability of modification.