Here we report the preparation and properties of polyethersulfone (PES) ultrafiltration (UP) membranes with poly(2-hydroxyethyl methacrylate) (PHEMA) grafted silica (SiO2) nanoparticles (PHEMA@SiO2 NPs) as the blending additive. The PHEMA@SiO2 NPs were First prepared by grafting PHEMA brushes onto SiO2 NPs via a surface-initiated reversible addition fragmentation chain transfer (RAFT) polymerization. The organic-inorganic hybrid membranes of PES with PHEMA@SiO2 NPs were fabricated via the traditional non-solvent induced phase separation (NIPS) process. During membrane formation, the hydrophilic PHEMA@SiO2 NPs tended to migrate toward the membrane top surfaces. The membrane surface porosities were increased and the surface hyclrophilicity was enhanced after introducing PHEIVIAOSiO(2) NPs. More importantly, the water permeability, solute rejection and anti-fouling ability of PES membranes were improved significantly. This phenomenon indicated that the trade-off between permeability and selectivity of PES LW membranes was broken by the incorporation of PHEIVIAOSiO(2) NPs. Different from traditional neat inorganic NPs additive, the PHEMA@SiO2 organic-inorganic NPs could be held in/on PES membrane for a long period of time clue to the intertvvisting of polymer chains. The present work provides a simple approach for stable and nearly permanent hydrophilization of PES UF membranes, which can also be extended to more membrane materials prepared by NIPS process. (C) 2013 Elsevier By. All rights reserved,