Composite membrane of silicone/PVDF was prepared by curing a copolymer of polysiloxane and phosphate ester cast on porous PVDF substrate. The substrate was previously plasma-grafted with a thin layer of silicone compatible material. The formed composite membrane was employed in pervaporation separation processes to separate ethanol-water solutions. It was found that the synthesized composite membrane exhibited excellent ethanol-permselectivity, particularly in the low ethanol concentration range. The separation factor of the composite membrane increased with increasing the thickness of the active silicone layer whereas the permeation flux follows a reversed order. In addition, multiple-layer composite membranes with an alternating silicone/PVDF/silicone configuration were prepared and tested for their separation capabilities. The results indicated that the membrane with four silicone layers gave the best performance with a separation factor of 31, permeation rate of 0.9 kg/m(2) h and PSI of 27,900 at a 10 wt.% ethanol feed concentration. (C) 2004 Elsevier B.V. All rights reserved.