Synthesis of photoreactive α-4-azidobenzoyl-ω-methoxy-poly(ethylene glycol)s and their end-on photo-grafting onto polysulfone ultrafiltration membranes

Covalent end-on grafting of poly(ethylene glycol) (PEG) onto a polysulfone (PSf) surface using α-4-azidobenzoyl-ω-methoxy-PEG (ABMPEG) is described. Photoreactive ABMPEG was synthesized by reacting monomethoxy-PEG (MPEG) with 4-azidobenzoyl chloride, yielding complete substitution of the hydroxyl groups. After adsorption from aqueous solutions, ABMPEG was photo-grafted under wet conditions onto PSf ultrafiltration (UF) membranes. Contact angle (CA) measurements showed the increased hydrophilicity of modified membranes and the irreversibility of the modification. Bovine serum albumin (BSA) adsorption decreased by 70% and the permeability decay after protein adsorption became less severe for the modified membranes compared to unmodified reference membranes.