PES-TiO2 composite membranes were prepared via phase inversion by dispersing TiO2 nanopaticles in PES casting solutions. The crystal structure, thermal stability, morphology, hydrophilicity, permeation performance, and mechanical properties of the composite membranes were characterized in detail. XRD, DSC and TGA results showed that the interaction existed between TiO2 nanopaticles and PES and the thermal stability of the composite membrane had been improved by the addition of TiO2 nanopaticles. As shown in the SEM images, the composite membrane had a top surface with high porosity at low loading amount of TiO2, which was caused by the mass transfer acceleration in exposure time due to the addition of TiO2 nanopaticles. At high loading amount of TiO2, the skinlayer became much looser for a significant aggregation of TiO2 nanopaticles, which could be observed in the composite membranes. EDX analysis also revealed that the nanoparticles distributed in membrane more uniformly at low loading amount. Dynamic contact angles indicated that the hydrophilicity of the composite membranes was enhanced by the addition of TiO2 nanopaticles. The permeation properties of the composite membranes were significantly superior to the pure PES membrane and the mean pore size also increased with the addition amount of TiO2 nanopaticles increased. When the TiO2 content was 4%, the. flux reached the maximum at 3711 L m (2) h (1), about 29.3% higher than that of the pure PES membrane. Mechanical test also revealed that the mechanical strength of composite membranes enhanced as the addition of TiO2 nanopaticles. (C) 2009 Published by Elsevier B. V.