The properties of composite membrane depend immensely on the quality of the interaction between the support layer and the active layer. This work describes the facile method to improve the interfacial adhesion of the chitosan (CS)/polyethersulfone (PES) composite membranes mediated by dopamine. A thin adherent poly-dopamine film was formed through the spontaneous deposition on top of the PES support layer, and acted as a transition layer. The CS active layer was subsequently coated on dopamine transition layer. The optimal recipe and procedure for CS/PES composite membrane preparation was as follows: PES support layer was treated with 4 mg ml(-1) dopamine solution (pH 9.47, dipping time 48 h). fully dried and then coated with crosslinked chitosan. The resulting CS active layer was about 10 mu m thick. The as-prepared CS/PES composite membrane exhibited high pervaporation flux of 2.28 kg m(-2) h(-1) for 90 wt.% aqueous alcohol solution in the feed at 80 degrees C. It could be derived that cloparnine mediation would be an effective method for preparing composite membranes with stable structural and high pervaporation flux. (C) 2009 Elsevier B.V. All rights reserved.