materials-letters-样本

MaterialsLetters163(2016)247–249ContentslistsavailableatScienceDirectMaterialsLettersjournalhomepage::Received29September2015Receivedinrevisedform9October2015Accepted12October2015Availableonline20October2015Keywords:ZnOnanoparticlesPhoto-inducedSwitchablewettabilityContactangleOil/waterseparationabstractWepresentaphoto-inducedmeshforon-demandoil/waterseparationbasedontheswitchablewett-ability.ThismultifunctionalcoatedsurfacewasfabricatedbysprayinghydrophobicZnOnanoparticles(NPs)andwaterbornepolyurethane(PU)mixturesonstainlesssteelmesh.Reversibletransitionbetweensuperhydrophobicityandsuperhydrophilicity/underwatersuperoleophobicityofthecoatedmeshcanberapidlyrealizedbyUVilluminationandheattreatmentalternately,whichallowstochangethemodeofoil/waterseparationfromoil-removingtowater-removing.Theoil-removingmodeallowsheavyoilsinoil–watermixturestopermeate,whilethewater-removingmodelettingwaterpermeate.Inaddition,thehighseparationefficiencywasachievedandthedriving-forcewasonlygravity.Allthesefeaturesmakethephoto-inducedZnOcoatedmeshanidealcandidateforon-demandseparationofvariousoil/watermixtures.&2015ElsevierB.V.Allrightsreserved.1.IntroductionWithgrowingaugmentofindustrialoilywastewaterreleaseandcrudeoilleakage,heightenedtechnologicalinterestinoil/waterseparationhasbecomeaworldwidesubject.Sinceoil/waterseparationisgovernedbyinterfacialphenomenon,theuseofspecialwettabilitytodesignnovelmaterialsisaneffectiveandfacileapproach[1].Recently,materialswithsuperhydrophilicity/underwatersuperoleophobicity(termedas“water-removing”typesofmaterials)haveattractedgreatattentioninthefieldofoil/waterseparation,becausetheyallowthewaterphasetopenetratethroughthematerialseasilywhiletheoilphasetoberepelledcompletely[2–5].The“water-removing”typesofmaterialsarewidelyutilizedduetothefactthatwatercommonlypossessesagreaterdensitythanoils.However,suchwaterremovalmaterialsarenotabestchoiceforseparationheavyoilfromwaterbecauseheavyoilaccumulatestoformabarrierlaidonthefilmsurfaceandpreventwaterpermeation.Inthiscase,itseemsanoptimalchooseforheavyoil/waterseparationtousematerialswithsuper-hydrophobicandsuperoleophilicproperties(namedas“oil-re-moving”typesofmaterials).Jiangetal.forthefirsttimefabricatedameshfilmpossessingbothsuperhydrophobicityandsuper-oleophilicitytoseparateoilfromwaterwiththeoilphaseper-meatedthroughthemeshquicklywhilethewaterphaseretainednCorrespondingauthor.Fax:þ869317971989.E-mailaddress:[e-mail](J.Li).[6].Subsequently,lotsof“oil-removing”typesofmaterialshavebeenfabricatedtoremoveoilfromwatereffectively[7–11].Althoughtheseparatewater-removalandoil-removalmaterialshavebeenextensivelyappliedinthefieldofoil/waterseparation,thebestoptionwilldependonthecompositionoftheoil–watermixtureandthedensityoftheoilinvolved.Therefore,thereisstillanurgentdemandforthepracticalseparationdevicethatshouldhavetheversatilitytohandlebothoptionsinonesinglefacility.Herein,wefabricateaphoto-inducedZnOcoatedmeshforon-demandoil/waterseparationbysprayingsuperhydrophobicZnOnanoparticles(NPs)andwaterbornepolyurethane(PU)mixturesonstainlesssteelmesh.Switchabletransitionbetweensuper-hydrophobicityandsuperhydrophilicity/underwatersuper-oleophobicityofthecoatedmeshcanberapidlyrealizedbyUVilluminationandheattreatmentalternately,whichallowstodealwithbothoptions(water-removingoroilremoving)inonesingleseparationdevice.Inaddition,thedrivenforceusedforoil/waterseparationisonlygravityandtheseparationefficiencyupto99.0%forlightoilandwatermixturesandabove97.0%forheavyoilandwatermixtureswasachieved.Furthermore,thereversibletransi-tionhasbeenrepeatedmorethan5timeswithhighseparationefficiency.2.ExperimentalHydrophobicZnONPswerepreparedaccordingtoourprevious248L.Yanetal./MaterialsLetters163(2016)247–249reportedwork[12].Indetail,hydrophilicZnONPswerefirstlyaddedto0.05Mstearicacidethanolsolutionandstirredfor6htogethydrophobicZnONPs.Then,themixtureof0.1gwaterbornepolyurethane(PU)and0.5ghydrophobicZnONPswasdispersedin40mLacetoneandstirredtogethomogeneoussuspension.Subsequently,thehomogeneoussuspensionwassprayedontothestainlesssteelmeshsubstrate(300mesh)with0.2MPacom-pressedairgas.Finally,themeshwasdriedatambienttempera-turetoallowtheacetonetoevaporatecompletely.Thesurfacechemicalcompositionoftheas-preparedsampleswasanalyzedonaPHI-5702electronspectrometerusingMgKαradiationastheexcitationsourceandthebindingenergieswerereferencedtotheC1sat284.80eV.Themorphologicalstructuresoftheas-preparedsurfaceswereexaminedbyfieldemissionscanningelectronmicroscopy(FE-SEM,JSM-6701F).Thewaterandoil