Organic　solvent　usually　was　used　in　a　polymer-based　membrane　fabricating　process.　In　this　study,　otherwise　pure　water　was　utilized　to　prepare　the　polymer　composite　membrane.　A　pure　aqueous　emulsion　was　firstly　prepared　through　directly　dissolving　a　commercially　available　amphiphilic　hyperbranched　polymer　(HBP),　Bottom　W3000　into　water.　As　the　cross-linking　agent,　glutaraldehyde,　glycol,　triethylamine,　or　tetraethyl　orthosilicate　was　then　added　into　the　emulsion,　respectively.　Finally,　the　HBP　was　self-assembled　onto　the　surface　of　polyacrylonitrile　(PAN)　ultrafiltration　membrane　by　immersing　the　PAN　substrate　into　the　emulsion　to　form　the　composite　membrane.　The　homogeneous　dispersion　of　the　HBP　in　the　emulsion　was　confirmed　by　transmission　electron　microscopy,　and　the　formation　of　the　composite　membrane　was　characterized　by　IR　spectra,　field　emission　scanning　election　microscopy　and　atomic　force　microscopy.　Importantly,　the　composite　membrane　performed　an　excellent　separation　performance　in　dye　retention　and　desalination.　For　example,　with　the　operation　pressure　of　0.5　MPa,　the　retention　of　methyl　blue　could　reach　97.0%　with　a　flux　of　55.0　L　m(-2)　h(-1),　while　the　salt　retention　was　lower　than　12.0%.　This　work　thus　not　only　illustrated　a　new　approach　for　the　preparation　of　nanofiltration　membrane　in　aqueous　solution,　but　also　produced　a　potentially　useful　polymer-based　composite　membrane　for　highly　efficient　dye　desalination.　(C)　2013　Elsevier　B.V.　All　rights　reserved.