Zwitterionic　monomer　carboxybetaine　methacrylate　(CBMA)　is　well　known　as　an　excellent　hydrophilic　and　ion　adsorption　material.　Herein,　we　created　a　PCBMA　layer　on　PVDF　membrane　surface　via　physisorbed　free　radical　polymerization　grafting　technique　(P-FFPG)　to　improve　its　hydrophilicity,　antifouling　and　inorganic　salts　separation　property.　The　key　factors　of　monomer　concentration　and　reaction　time　which　influence　grafted　density　(GD)　were　investigated　in　the　present　work.　Attenuated　total　reflectance-Fourier　transform　infrared　spectroscopy　(ATR-FTIR)　confirmed　that　the　CBMA　monomer　was　grafted　onto　the　membrane　successfully.　The　surface　chemistry　composition　was　conducted　via　X-ray　photoelectron　spectroscopy　(XPS).　Scanning　electron　microscopy　(SEM)　analysis　clearly　showed　that　the　PCBMA　layer　formed　on　the　membrane　surface,　and　its　grafted　degree　increased　with　the　monomer　concentration.　The　water　static　contact　measurement　confirmed　that　modified　PVDF　membranes　obtained　stable　enhanced　hydrophilicity　and　superior　water　adsorption　ability.　The　static　protein　adsorption　at　different　pH　showed　a　partly　pH　sensitivity　and　an　improving　antifouling　ability　almost　in　the　whole　pH　range.　The　ultrafiltration　experiments　suggested　that　the　anti-protein　fouling　of　the　grafted　membranes　was　significantly　improved.　The　modified　membrane　possessed　a　stable　initial　sodium　chloride　(NaCl)　rejection　ratio　and　reversible　flux　behavior.　©　2014　Elsevier　B.V.