Poly (lactic acid) hollow fiber membranes with poly (lactic acid)-polyethylene glycol-poly (lactic acid) (PLA-PEG-PLA) triblock copolymers were synthesized using different molecular weight PEG segments, and were used as hydrophilic copolymers for the preparation of PLA/PLA-PEG-PLA blend hollow fiber membranes. The effects of the addition of PLA-PEG-PLA copolymers with different PEG segment lengths on the membrane morphology, hydrophobicity, and filtration performance were studied. Fouling experiments performed using BSA indicated that PLA-PEG-PLA copolymers with longer PEG segment lengths were more effective in improving the antifouling properties of the hollow fiber membranes, because of the higher retention of the synthesized copolymer additive in the membrane. (C) 2013 Elsevier B.V. All rights reserved.