單分散納米二氧化硅的制備與表征(Preparationand

characterizationofsingledispersednano-silica)Thefirst27rollsfirst1phasesilicatethroughVol.27No.1In2008,OnFebruaryBULLETINOFTHECHINESECERAMICSOCIETYFebruary,2008,Preparationandcharacterizationofsingledispersednano-silicaFuYuanXiang,SunYanhuiGeXingheartSouthChinanormaluniversity,chemistryandenvironmentGuangzhou,510006).Inthispaper,Stobersol2gelmethod,thecompositionisaboutthesize80~150nmsingledispersednano-silicamicrospheresAndthetemperatureandammoniaconcentrationarediscussedDegreeandTheinfluenceofTEOSconcentrationandotherfactorsonthesynthesisofsilica.usingThesampleswerecharacterizedbyXRD,IR,SEMandTEM.TheresultstableMing:theincreaseofhydrolysistemperatureacceleratesthematurationofsilicaparticlesinsolution;TheincreaseinammoniaconcentrationincreasesnucleationspeedHydrolysisvelocityplusDrama,TheparticlesizeofsilicondioxideincreasesAndthedegreeofreunionalsoincreases.TheincreaseofTEOSalsoresultsinaslightincreaseinthesilicaparticlesizeTheextentofreunionisdeepened.keywords:monodisperse;nanoSiO2.sol2gelmethodIntermediatenumber:TQ127FUYuan2xiang,SUNYan2hui,GEXing2xinDocumentidentificationcode:Aarticlenumber:100121625(2008)2008SynthesisandCharacterizationofMonodisperseSiO2nanoparticles(SchoolofChemistryandEnvironmentSouthChinaNormalUniversity,Guangzhou510006,China)Abstract:AStOberSol2gelmethodhasbeenusedtopreparemonodisperseanduniform2sizefrom80Inthispaper,ThesilicaparticleswereobtainedbyhydrolysisoftetraethylInethanolmediumuseammoniumascatalystandadetailedstudywascarriedoutorthosilicate(TEOS)Ontheeffectofcompany'stemperature,theamountofammoniumandTEOSonparticlesizesandtheDispersion.ThestructureofThesamplewasexaminedbyXRDandThechemicalbondofThesampleSurfacewasexaminedbyFT2IR.TheparticlesizeandThedispersionwereexaminedunderscanningElectronmicroscopyandtransmissionelectronmicroscopyTheresultsobtainedinthisstudyshowedthatThehighhydrolysistemperaturespeeduptheSiO2conglomerationinthesolution.Moreover,theparticleSizeandthedispersionofSiO2obtainedwereincreasingwiththeincreasingofamountsofammoniumandThereasonthatthehydrolysisspeedandnucleationspeedwasincreased.Keywords:monodisperse;SiO2nanoparticles;sol2geltheintroductionSiO2isanontoxic,odorless,pollution-freenon-metallicmaterial.nanoTheSiO2ismicro-sizedduetoparticlesizeThesurfaceareahasincreaseddramaticallymakeSiO2nanoparticleshavemanyuniquepropertiesandwideapplicationprospectsSuchasspecialphotoelectriccharacteristics,highmagnetoresistanceandnonlinearresistancelikeAthightemperature,itstillpossessesstrangepropertiessuchashighstrength,toughnessandstability[125].InadditionSilicondioxideisduetoitsopticaltransparency,chemicalinertia,andbiologicalCapacitiveetc.Itplaysanimportantroleinmodernnewmaterialsandcompositenanomaterials.ManyresearchersuseasingledispersionSiO2microspheresfornucleusorshell[6210]Alotofnewmaterialshavebeenprepared.SothemonodispersenanometerSynthesisofSiO2microspheresandtheirparticlesizecontrolIntheactualstudyIt'sgettingmoreandmoreimportant.Author'sbriefintroduction:FuYuanXiang(19782),male,master'sdegreeStudyontheluminescenceofrareearthnanomaterials.Correspondingauthor:SunYanhui,E2mail:sunyanhui0102@163.ComThefirst1Thepreparationandcharacterizationofsingledispersednano-silica155ThepreparationofnanometerTherehavebeenmanyreportsofSiO2microspheres[11213],sinceStoberetal.proposedanaqueoussolutionoforthosilicateinanalcoholmedium(TEOS)tosynthesizeasingledispersedsilicondioxidemethodThesingledispersedsilicondioxidehasbecomeoneofthemoststudiedsingledispersedsystems.ThisisnotonlyBecauseofthismethodtheparticleshavegooddispersibility,sizecontrollableAndbecauseofthesilicondioxideonthesurfaceofsilicondioxide,itisverysuitableforthemodifiedbridgebeamMakeitfunctional.Theevolvingtechnologyprovidesnewopportunitiesforitsexpandingapplicationareas.SolgelmethodisusedinthispaperInthecontrolTEOS,ammoniaconcentrationandreactiontemperature,theparticlesizeissynthesized80~150nmfanTheenclosedmonodispersenanometerSiO2particlesAnduseXRD,IR,SEM,TEM,etc.experimentalpart2.1rawmaterialsandreagentsTetraethylorthosilicateTetraethyl(tetraethyl),TEOS),analyticalpureSiO2contentisnotlowerthanthat28percent,tianjinfuchenchemicalreagentplant;ThereisnowaterethanolCH3CH2OH,that'spureTianjindamaochemicalreagentfactory;ammonia(NH3H2O),content2528%,tianjindaomaochemicalreagentfactory25Deionizedwater(H2O)madefrompurewater.2.2characterizationmethodsThreehundredtransmissionelectronmicroscopy(tem)wasusedtotestthesampledissolvedinanhydrousethanol.ThestructureofSiO2isusedindandongraysType2y2000transfertargetX2-raypowderdiffractometerdeterminationwithCuKatargetin2thetavalueis~80°Inorderto°/minvelocitymeasurement.NipponIRPrestige221-typeinfraredspectrometertodeterminetheinfraredspectrumofthesample,pureKBristhebasesampletestInthewavenumberrangeMeasurementof4500~0cmT.TheshapeandsizeofthegranulesQuanta400,PhilipsscanningelectronmicroscopyandHitachiHitachi2ThesynthesisofsilicananoparticlesInstallthemixeronthe500mL3flask,returnthecondensertube,MixwellandeventuallyaddTEOStowaterbathreactionatspecifiedhydrolysistemperature.Separatedbyhigh-speedcentrifugationThethermometerLet'sstartwithanhydrousethanolAndyoumixitwithammoniaMorethan5minAndmakethesolutionSiO2spheresAndthenyouuseanhydrousethanolRepeatedcentrifugationUntilthesolutionisneutraldryingSiO2powders.Thispaperdiscussesthehydrolysistemperatureandtheamountofammonia.TEOSdosageandsoonTheeffectofsyntheticmonodispersenano-silicaresults.3resultsanddiscussion1reactionmechanism[14]TheparticlesizeofSiO2isaffectedbythewaterofthereactant,theconcentrationofammonia,thetypeofsilicateester,thetypeofdifferentalcohols,thekindsofcatalystsandthedifferenttemperatureItsdifferent.ThroughtheregulationofthesefactorsCanobtainvariouskindsofstructurenanomaterials.InanalkalineenvironmentThehydrolysisofethylsilicateThecondensationreactionistwostepsThefirststep::hydrolyticreactionThehydroxylationofethylsilicatehydrolysisandthecorrespondingalcohols;Thesecondstep:siliconacidorsiliconThereisacondensationreactionbetweenacidandethylsilicate.Infact,thefirststepandthesecondsteparegoingtobesimultaneousTheprocessisverycomplicated,sobeItisalmostimpossibletodescribethehydrolysisandcondensationprocessindependentlyReactionproductsarecolloidalparticlesofdifferentsizesandstructures.Studylettersofsilicatebulletintwenty-sevenTEOSmoleculesThefoursmalleroxygensarenotenoughtocompletelysurroundthepositivelychargedsiliconions,therearedirectexposure.InthealkalitorushUndertheconditionoftheSmallradiusOH2directlylaunchesnucleophilicattacktocompletehydrolyticreactionAndasyougetridofthealkoxideTheelectropositivepropertiesofsiliconatomsincreaseAnd,SpatialfactorsaremorefavorableThepro-nuclearattackhasbecomeeasierSointhebasecatalysisconditionTEOShydrolysisisrelativelycompleteThehydrolyzedmonomercontainsmoreMuchoftheSi2OHgroupThehydrolyticproductsarerecondensationinmultidimensionaldirectionwithacertainamountofnucleationToformsphericalparticles.3.Theeffectof2reactiontemperaturefigurea,1Bisthereactiontemperature29°Cand42C,otherreactionconditionsTEOS0.022mol,ammonia0.112mol,CH3CH2OH1.71mol,H2O0.55molTheSiO2XRDdiagrams.BythefigurethevisibleAtthetworeactiontemperatures,thesamplediffractionpeakappearsinThelocationofthe2theta=22°,thishastodowithThecharacteristicsofSiO2areconsistentwithstandardCARDS(JCPDSNo.2920085),indicatingthatwithinacertainrangeofreactiontemperature,ThechangeoftemperaturehaslittleeffectonthedegreeofcrystallizationSoyoucangettheperfectcrystallizationSamplesofSiO2.figureSiO2nanoparticlesXRDspectraFig.1X2raydiffraction(XRD)patternoftheSiO2nanoparticles(1)attemperatures(A229°C,B242C),(2)theatdifferentNH3H2Oconcentrations(C20.07mol,D20.Mol,70).(3)atTEOSconcentrations(E20.013mol,F20.100mol)figurea,b,respectivelyInfraredspectrogramofsamplesat2reactiontemperatures.Bythefigure2thevisibleAndtheybasicallyoverlapthepeaks,butItsnotthesameintensity,includingInthesamplemade29°CAnd1120cm-1Thepeakratiois3540cmT42Csharp.Thetemperatureistoohigh,ammoniawieldSendfasterThecatalyticreactionefficiencyisaffected.figure2.InfraredspectrogramofSiO2nanoparticlesFig.2IRpatternsofthesixSiO2nanoparticles(1)attemperatures(A229C,B242C),(2)theatdifferentNH3H2Oconcentrations(C20.07mol,D20.70mol).(3)atTEOSconcentrations(E20.013mol,F20.100mol)Thefirst1Thepreparationandcharacterizationofsingledispersednano-silica157Spectrumin1000~1150cm-1hasaverywideabsorptionpeakThepeak,in1120cm-1.TheycorrespondtotheSi2O2Si'shorizontalandverticalsymmetryVibrationreductionpeakThevalencebondisatthesametimeAt805cmT,symmetricalsystolicvibrationpeaksandBendingvibrationpeakat476cmT.Thepeakof476cmTisIntheSiO2Sischaracteristicpeak.Amongthem~3600cm-1isthesiliconhydroxylvibrationpeakIngeneral:3750cm-1correspondstothesurfacefreesilanolvibrationpeak;3663cm-1correspondstothesiliconhydro-bondingofthesilicon-alcoholbasevibrationpeak;3550~3400cm-1isthevibrationpeakassociatedwiththesurfaceadsorptionhydrogenbond.InthefigureThe950~960cm-1didnotappearobviousSi2OHstretchingvibrationpeakIt'snotthatitdoesn'texistButintheAnd1120cm-1805cm-1ThepeakistoostrongTherangeistoolargeAndcoverupthepeakatthislocation.figurea,3BistwosamplesofdifferentsynthetictemperaturesSEMtopographyFromthefigureSoyoucanseethatin3A29°CcompositeparticlesTheparticlesizeofabout80nm,it'sbettertobedecentralizedItsbasicallynotreuniting.while42CwhentheparticlesizeisaboutAround100nmThedispersionispoorThatpartofthestarThegrainsarereunited(FIG.3b).ItcanbeseenthatAsthereactiontemperatureincreasesTheparticlesizeofsilicaspheresincreasedslightlyThereunionismoreserious.Thismaybeduetotheincreaseofhydrolysistemperature,whichacceleratesthematurationofsilicaparticlesinsolution.figureScanningelectronmicrographof3SiO2nanoparticlesFig.3SEMmicrographsoftheSiO2nanoparticles:(1)attemperatures(A229°C,B242C),(2)theatdifferentNH3H2Oconcentrations(C20.07mol,D20.70mol).(3)atTEOSconcentrations(E20.013mol,F20.100mol)figurea,bisthesampleTEMphotos.Bythefigure4thevisibleSample:TheparticledispersionofAisbetterthanthesampleB'suniform,particleshapeTherulesaregood.FromwhathasbeendiscussedaboveForthecompositionusedinthisarticleTheconditionofSiO2Thelowtemperatureisconducivetothecontrolofparticlesizeandtheadjustmentofdispersion.figurec,figure1disinTeos0.022mol,CH3CH2OH1.71mol,H2O0.55mol,temperature29°CunderdifferentammoniaconcentrationTogettheThesamplesofSiO2XRDdiagrams.BythefigurethevisibleChangeintheconcentrationofammoniaThedegreeofcrystallizationofSiO2isnotsignificant.figurec,Onthe2dforTheinfraredspectrogramofthetwosamplesisdescribed.AmodestchangeintheamountofammoniaTheformationofSiO2hadnosignificanteffect.figurec,d,c,dScanningelectronmicroscopyandtransmissionelectronmicroscopy(tem)ofthesetwosamplesweretakenrespectively.Bythefigure3,figure4thevisible0.07molofammoniasynthesisofparticlesthan0.70molofammoniasynthesishasasmallerparticlesize,andit'sbetterforregularityanddispersion(FIG.3c).figureThesizeofSiO2particlesisobviousNotthesameAndsomeoftheparticlesaretogether.YoucanseetheconcentrationofammoniaThesizeanddispersionofSiO2havesignificantinfluence.InvestigateitsreasonfromStoberalkalinecatalytichydrolysispreparationTheactionmechanismofammoniainSiO2isexplained[15].BecauseofthebasecatalyticconditionUndertheTEOShydrolysisisThenucleophilicreactionmechanismofh-iondirectlyattackingsiliconnucleiThere'slessinthemiddleAnd,OHminustheradiusissmallSothehydrolysisvelocityRateisfast.ThesilicicacidformedbyhydrolysisisaweakacidItbecomesastrongbaseunderalkalineconditionsTheothersiliconnucleimustbeinitiatedAnuclearattackAnddehydration(ortakeoffalcohol)polymerizationButthispolymerizationhasagreateffectonresistanceThepolymerizationrateisslow.ItishydrolyzedinabasecatalyticsystemResearchlettersofsilicatebulletintwenty-sevenTherateisgreaterthanthepolymerizationrateAnd,TEOShydrolysisiscompleteTherefore,itcanbeconsideredthatpolymerizationiscarriedoutinmultidimensionaldirectionundertheconditionsofhydrolysistheToformashortlinkstructureThepolymerizationofthisshortchaincrosslinkingstructureTokeeptheshortchaincrosslinkingupAndfinallyformsphericalparticles.DuetotheThisammoniaisthemainfactoraffectingthemorphologyofparticlesInotherconditionsAndastheconcentrationofammoniaincreasesInthesolution,OH-concentrationincreasedThehydrolysisofethylorthosilicateThesaturationofthesolutionincreasesAndthenumberofnucleonisincreasing.Atthesametime,theconcentrationofammoniaisincreasingAlso,NuclearaccumulationhasbeensignificantlypromotedTheaverageconcentrationincreasedrapidly,Sotheparticlesizeofthesilicondioxideparticlesisincreasing.SoastheTheammoniaconcentrationincreasesThesizeofsphericalsilicaisincreasedAndthedegreeofreunionalsoincreases.Rui-yuzhaoetc.[16]theprocessofformationofsingledispersingsilicaparticlesisacomplexprocessbetweenhydrolysis,nucleationandparticlegrowth.HydrolysisisthecontrolstepofthewholereactionprocessNucleationisformedattheearlystageofthereactionThefactorsthatpromotehydrolysisalsopromotenucleationandgranulesGrowthfactorVisible,TheamountofammoniacanhelpdispersethenanometerTheformationofSiO2.3.TheinfluenceofTEOSdosageCondensationpolymerization.InthehydrolyticreactionThealkoxy(OR)byHydroxidesubstitution,condensationpolymerizationAftertheconcentrationofSi2OHreachesthecriticalnucleationconcentration,thereisanewnucleation.Si2O2Sikeysandwater(H2O).TEOSasthereactionsourcematerialcontinuouslyhydrolyzesoutcomponentsSi2OH,whenfigure1e,figureThe1FisthereactionconditionCH3CH2OH1.71mol,ammonia0.112mol,H2O0.55mol,temperature29°CwhenChange,TEOSusageThesamplesofSiO2XRDspectra.figureE,figure22FistheinfraredspectrogramoftheabovetwosamplesAnditturnsoutthat,TEOSThegreatertheamountofIntheAnd1120cm-13540cm-1themoresharpthepeakThestrongerthepeak.figure3e,figure3Fistheabove2.ScanningelectronmicroscopyofsamplesSlice.ThedispersionofthetwosamplesisbetterAndtherulesoftheparticlesarebetter.Amongthem013molTEOSSiO2phasefor100nm,0.100molteos,thesyntheticSiO2nanoparticleshaveaslightlylargersize,about150nm.YoucanseethatTEOSshouldnotbetoolarge.TEOS,themainreactantofthesystem,ishydrolyzedbythecatalyticactionofammonia.0.100molesofTEOSTheparticlesofSiO2aresmall.figure4e,4FisthetransmissionelectronmicrographoftheabovetwosamplesSample,productEandsampleThedispersionandruleofFarebetter.in013molTEOSThesizeoftheSiO2nanoparticlesisaboutTheformationvelocityofsingledispersioncolloidalnucleationandthegrowthrateofcrystalareallrelatedtothesaturationdegree[17].IftheoversaturationisnotproperlycontrolledTomakeTheformationofnucleusandthegrowthofnucleationaresimultaneousYougetapolydispersegel.BecauseofthecoreofthenucleationandtheresultingkernelThechildrenarenotgenerallylarge.IfthenucleationisformedandthegrowthisseparatedBycontrollingthesaturationTomakealargenumberofcoresoveraperiodoftimeItsnotgoingtobethenucleusanymoreOnlythegrowthprocessThesizeofthecolloidalparticlesisequaltoone.figureThetransmissionelectronmicrographofSiO2nanoparticlesFig.4TEMmicrographsoftheSiO2nanoparticles:(1)attemperatures(229°C229C,B),(2)theatdifferentNH3H2Oconcentrations(C20.07mold20.Mol,70),(3)atTEOSconcentrations(E20.013molf20.Mol,013)Thefirst1Thepreparationandcharacterizationofsingledispersednano-silica159Fromfigure4e,Youcanseethatin4FTheamountofTEOSisincreasingWhen0.1mol,TheparticlesizeofSiO2increases.ThesechangesaremainlyduetoInthesystemThechangeofTEOSconcentrationcausedthechangeofhydrolysisandpolymerizationrate.TheincreaseofethylsilicateconcentrationincreasestherateofhydrolysisTheresultingThechainofthree-dimensionalnetworksisalsolongerInthecondensationprocessThelongerthree-dimensionalnetworkstrandsareinterwoventogetherThepolymerizationdegreeisalsolargerTheresultingparticlesThesizeoftheparticleincreases.ButintheTEOSconcentrationislowThesystemhydrolysisandpolymerizationrateisrelativelyslowThenucleationandgrowthofgranulesareslow,soSiO2starTheparticlesizeissmall.4conclusionpreparationofethylsilicatehydrolysisSiO2,When29°Cthaninsyntheticsamples42CwhenthedispersionandparticleinsyntheticsamplesThesexisbetter.ThetemperatureistoohighHydrolysisofammoniaTEOSdoesnotreactwell.inammoniaconcentration07molofsyntheticsamplesarebetterthanthosein0.70molconcentrationofthesynthesizedsampleswaslightIt'salsoaruleSaid,MingThehighertheconcentrationofNH3?H2Othelargertheparticlesizeandsizeofthesyntheticsample.inWhenTEOSconcentrationislarge,thesamplesizeislargerItsalittlebitlessdispersible.referenceapplyingNozawaK,GailhanouH,etal.Smartcontrolofmonodispersestober:Langmuir,2005,21:151621523.I,shaoleiChen,Synthesisandcharacterizationofmonodispersioncolloidalorganic2silicathespheres[J].SiO2coatingnanometerCaCO3transmissionelectronmicroscopycharacterization[J] .Analysisoftestjournals2006,25(3):1032105.[2]shi-quanliu,WangLiminFu-tianliu,Preparationand