In this study, carboxylic polyethersulfone (CPES) was prepared by controlled acetylating and oxidating reaction, and then used for preparing functional polyethersulfone (PES) membranes by blending method, and the blending ratios of CPES to PES were 1:10, 1:4 and 1:2 (weight ratio), respectively. After blending with the CPES, the water contact angles (WCAs) of the membranes decreased from about 57.3 degrees to 35.0 degrees. The modified hollow fiber membranes showed significant pH-sensitivity and pH-reversibility; the pH-valve effect was observed at the pH values ranged from 5 to 10. In addition, the fluxes of the blended hollow fiber membranes increased with the increase of the blended CPES amounts. The bovine serum albumin (BSA) adsorbed amounts for the membranes decreased from 17.6 mu g/cm(2) to 7.6 mu g/cm(2), and the blended membranes showed good protein antifouling property. The metal ionexchange experiment indicated that the membranes could be used to bind heavy metal ions. (C) 2011 Elsevier B.V. All rights reserved.