In　the　past　decades,　the　layer-by-layer　(LBL)　adsorption　of　oppositely　charged　polyelectrolytes　has　proven　to　be　a　promising　method　for　the　preparation　of　polyelectrolyte　multilayer　membranes.　However,　to　obtain　a　good　separation　capability,　LBL　adsorption　involved　relatively　long　periods　because　50-60　bilayers　were　normally　required.　The　aim　of　this　study　was　to　develop　such　a　new　method　that　would　allow　simplification　of　the　LBL　procedure.　LBL　adsorption　was　proposed　to　proceed　under　a　dynamic　condition　to　prepare　polyelectrolyte　multilayer　membranes.　The　polyacrylic　acid　(PAA)　and　polyethyleneimine　(PEI)　were　alternatively　deposited　on　polyethersulfone　(PES)　ultrafiltration　support　membrane　under　a　pressure　of　0.1　MPa.　The　polyelectrolyte　multilayer　membranes　prepared　by　dynamic　LBL　process　were　compared　with　those　prepared　by　the　static　LBL　process　for　the　pervaporation　separation　of　water-ethanol　mixture.　The　results　suggested　that　a　relatively　high　separation　factor　could　be　obtained　with　only　four　composite　bilayers　by　using　dynamic　LBL　process.　The　preparative　conditions　including　bilayer　number,　filtration　time　of　the　first　PAA　layer,　reaction　time,　ratio　between　polayanion　and　polycation　concentrations,　PAA　molecular　weight　and　salt　addition　were　investigated.　The　pervaporation　conditions　such　as　feed　temperature　and　water　concentration　in　the　feed　were　also　evaluated.　Under　the　temperature　of　40　degrees　C,　the　separation　factor　and　the　permeate　flux　of　the　polyelectrolyte　multilayer　membranes　were　about　1207　and　140　g/(m(2)h),　respectively.　(c)　2006　Published　by　Elsevier　B.V.