简介：Anovelhydrophilicnanocompositeadditive(TiO2-g-PNIPAAm)wassynthesizedbythesurfacemodificationoftitaniumdioxide(TiO2)withN-isopropylacrylamide(NIPAAm)via"graft-from"technique.Andthenanocompositemembraneofpoly(vinylidenefluoride)(PVDF)/TiO2-g-PNIPAAmwasfabricatedbywetphaseinversion.Thegraftdegreewasobtainedbythermo-gravimetricanalysis(TGA).Fouriertransforminfraredattenuatedreflectionspectroscopy(FTIR-ATR)andX-rayphotoelectronicspectroscopy(XPS)characterizationresultssuggestedthatTiO2-g-PNIPAAmnanoparticlessegregatedonmembranesurfaceduringthephaseseparationprocess.Scanningelectronmicroscopy(SEM)wasconductedtoinvestigatethesurfaceandcross-sectionofthemodifiedmembranes.ThewatercontactanglemeasurementsconfirmedthatTiO2-g-PNIPAAmnanoparticlesendowedPVDFmembranesbetterhydrophlilicityandthermo-responsivepropertiescomparedwiththoseofthepristinePVDFmembrane.Thewatercontactangledecreasedfrom92.8°ofthePVDFmembraneto61.2°ofthenanocompostiemembrane.Bovineserumalbumin(BSA)staticanddynamicadsorptionexperimentssuggestedthatexcellentantifoulingpropertiesofmembraneswasacquiredafteraddingTiO2-gPNIPAAm.ThemaximumBSAadsorptionat40°Cwasabout3timesthanthatat23°C.ThepermeationexperimentsindicatedthewaterfluxrecoverratioandBSArejectionratiowereimprovedatdifferenttemperatures.

简介：Asupercriticalcarbondioxide(ScCO2)assistedphaseinversionwasdevelopedtoproducemicroporouspoly(vinylidenefluoride)(PVDF)membraneswhosemorphologycharacteristicsarisefrombothliquid-liquiddemixingandsolid-liquiddemixing(crystallization).ThisresultwasconfirmedbyFouriertransforminfraredspectroscopy(FTIR),fromwhichbothαandβcrystalswerefound.Asrevealedbycontactangleexperiment,thePVDFmembranespreparedviaScCO2assistedphaseinversionweremorehydrophobiccomparedwiththecontrolmembraneproducedviaconventionalimmersionprecipitationtechnique.Inparticular,thesamplewith15wt%PVDFpreparedat45°Cand13MPaexhibitedacontactangleof142°,whichwasmainlycausedbythemultilevelmicro-andnano-structure.Theeffectsofpolyethyleneglycol(PEG),polyvinylpyrrolidone(PVP)andlithiumchloride(LiCl)onthestructuresandcrystalformwereinvestigated.PVPpromotedtheformationofβphasecrystalform,whilePEGbooststheevolutionofαphase.LiClrestrainedthecrystallizationdegreeofPVDFmembraneunderScCO2.

简介：