Polydimethylsiloxane(vi)-poly(vinylidene fluoride) (PDMSvi-PVDF) composite membranes were prepared using asymmetric PVDF hollow-fiber membranes as the substrate where a very thin layer of silicone-based coating material was deposited via a developed dip coating method. The preparation of the composite membranes under various conditions were investigated. In the optimal coating procedure, homogenous and stable oligo-PDMSvi coating layers as thin as 1-2 mu m were successfully deposited on the surface of PVDF membranes. The developed PDMS-(v1)-PVDF composite membranes were applied for separation of a wide variety of volatile organic compounds (benzene, chloroform, acetone, ethyl acetate, and toluene). The results showed that the PDMSV1-PVDF hollow-fiber composite membranes that had been developed exhibited very high removal efficiency (> 96%) for all the VOCs examined under favorable operating conditions. (c) 2005 Wiley Periodicals, Inc.