Vapor　permeation　seems　to　be　a　more　suitable　separation　process　than　pervaporation　in　bio-ethanol　recovery　from　fermentation　broth　because　of　its　non-direct　contact　trait.　The　unsatisfactory　flux　and　selectivity　of　polymeric　membranes　limit　their　utilization　in　industrial　application.　Here,　we　tailored　the　physical　and　chemical　structure　of　commercial　available　polyacrylonitrile　(PAN)　ultrafiltration　membrane　to　serve　in　vapor　permeation.　The　membrane　porosity　was　reduced　till　dense　enough　for　separation　while　preserving　an　ultra-high　flux　by　hydrolyzing　in　alkali.　The　hydrophilicity/hydrophobicity　was　controlled　by　grafting　fluoroalkyl　chains　to　ensure　an　acceptable　ethanol　selectivity.　The　changes　of　physical　structure　and　chemical　property　were　systematically　characterized　by　Fourier　transform　infrared-attenuated　total　reflectance　(ATR-FTIR),　X-ray　photoelectron　spectroscopy　(XPS),　scanning　electron　microscopy　(SEM),　water　contact　angle　and　pure　water　permeance.　Tested　at　60　degrees　C,　the　optimized　membrane　exhibited　a　high　flux　of　ca.　10.5　kg　m(-2)　h(-1)　and　a　permeate　ethanol　content　similar　to　vapor-liquid　equilibrium　curve,　which　outstripped　most　polymeric　membranes　(applied　in　pervaporation　or　vapor　permeation)　in　both　flux　and　selectivity.　(C)　2019　Elsevier　Ltd.　All　rights　reserved.