Membrane　support　properties　influence　the　performance　of　thin-film　composite　nanofiltration　membranes.　We　fabricated　several　polysulfone　(PSf)　supports.　The　physicochemical　properties　of　PSf　were　altered　by　adding　polyethylene　glycol　(PEG)　of　varying　molecular　weights　(200-35,000　g/mol).　This　alteration　facilitated　the　formation　of　a　thin　polyamide　layer　on　the　PSf　surface　during　the　interfacial　polymerization　reaction　involving　an　aqueous　solution　of　piperazine　containing　4-aminobenzoic　acid　and　an　organic　solution　of　trimesoyl　chloride.　Attenuated　total　reflectance-Fourier　transform　infrared　validated　the　presence　of　PEG　in　the　membrane　support.　Scanning　electron　microscopy　and　atomic　force　microscopy　illustrated　that　the　thin-film　polyamide　layer　morphology　transformed　from　a　rough　to　a　smooth　surface.　A　cross-flow　filtration　test　indicated　that　a　thin-film　composite　polyamide　membrane　comprising　a　PSf　support　(TFC-PEG20k)　with　a　low　surface　porosity,　small　pore　size,　and　suitable　hydrophilicity　delivered　the　highest　water　flux　and　separation　efficiency　(J　=　81.1　+/-　6.4　Lm-2h-1,　R-Na2SO4　=　91.1%　+/-　1.8%,　and　R-NaCl　=　35.7%　+/-　3.1%　at　0.60　MPa).　This　membrane　had　a　molecular　weight　cutoff　of　292　g/mol　and　also　a　high　rejection　for　negatively　charged　dyes.　Therefore,　a　PSf　support　exhibiting　suitable　physicochemical　properties　endowed　a　thin-film　composite　polyamide　membrane　with　high　performance.