The　purpose　of　this　study　is　to　provide　some　fundamental　understanding　for　the　design　of　industrial　hollow　fiber　pervaporation　membrane　module.　Inner　skin　hollow　fiber　pervaporation　membrane　modules　were　fabricated　by　a　dynamic　negative　pressure　layer-by-layer　(LbL)　technique.　The　influences　of　dynamic　negative　pressure　and　recycling　velocity　of　polyelectrolyte　solutions　on　the　formation　of　non-porous　selective　layer　were　firstly　investigated　using　mini-modules　during　the　dynamic　assembly　process.　Since　none　of　reported　works　dealt　with　the　effects　of　packing　density　of　hollow　fiber　module,　pilot-scale　modules　(diameter　x　length　=　1　in.　x　20cm)were　therefore　prepared　by　filling　different　amounts　of　hollow　fibers　into　a　membrane　shell.　The　experimental　results　show　that　the　higher　packing　density　of　500　m(2)/m(3)　rendered　both　total　flux　and　selectivity　to　decrease　significantly.　As　for　a　I　m　long　module　that　has　been　commonly　used　in　industry,　further　investigations　were　conducted　using　a　1-m　long　hollow　fiber　module.　The　vacuum　drop　along　the　axial　direction　of　hollow　fibers　was　noted,　especially　near　to　the　vacuum　suction　opening.　Despite　of　this,　the　relatively　high　and　stable　selectivity　could　be　obtained　even　the　fiber　length　increased　to　1　m.　(C)　2009　Elsevier　B.V.　All　rights　reserved.