嵌段共聚物自组装纳米薄膜

Free-StandingNanomaterialsfromBlockCopolymerSelf-Assemblyllye88化学所MainReferenceOutlineIntroductionExperimentalPartResultsandDiscussionConclusionsInnovationsandProblemsReferences1.

IntroductionAmphiphilicblockcopolymers(BCs)couldcontrolmaterialinterfaces.The3DconstructionisdirectedbytheassemblyofBCsmicellespreparedinsituduringthespin-coatingoftheblockcopolymersolution.BCsinselectivesolventleadtothepreparationofcore-shellmicelleswithadenseinsolublecoreandadiffuseshellpartiallyswollenbythesolventadenseinsolublecore内核

micelles

adiffusecorona核冠Inthiswork，thepreparationofstablenanostructureassembliesinonestepfromhomogeneoussolutionsofABAtriblockcopolymers.Thesuccessofthisstrategyisessentiallyduetothedesignofverystablemicellespreparedandself-assembledinsituinfewsecondsbysolventevaporationSelf-AssemblyNanomaterialsTheglassyPSANblockswillenabletheformationofcompactaggregatesconstrainingthemicellestobekineticallyfrozenatroomtemperaturewhereastheflexiblePEOblockwillenablethedynamictransitionsbetweenlooped

andbridgedchainconformations.looped

bridged

PhotonCrossCorrelationSpectroscopyPhotonCrossCorrelationSpectroscopy（PCCS），光子交叉有关光谱法PCCS已用于纳米颗粒粒径测量,其技术日益成熟并成为纳米颗粒粒径测量旳有效措施。其测量原理是建立在颗粒旳布朗运动之上。伴随颗粒旳布朗运动,散射光强围绕某一平均值不断起伏涨落。PCCS能够直接测试高浓度试样而不需要稀释。测量成果完全真实旳反应了被测试样品旳实际粒度及分布状态PCCS测定旳参数为：平均粒径和多分散指数吴立敏，王晓艳.纳米、亚微米颗粒粒度旳测量——光子有关光谱法,《上海计量测试》，2023年30卷3期2.ExperimentalPartSythesisoftheTriblockCopolymera.EsterificationPEO+AcryloyolChloride（丙烯酰氯）PEO-acrylate(I)b.IntermolecularRadicalAdditionI+MAMA-SGIalkoxyaminemacroalkoxyamine-basedPEO(II)c.PreparationofTriblockCopolymerII+Styrene+Arylonitrile

P(St317-co-AN262)-b-PEO795-b-P(St-co-AN)PreparationofPolymerFilmsa.DissolvingtheTriblockCopolymerinaDMF/toluenemixtureb.Spin-coatingthehomogeneoussolutionontoaSiwaferevaporatesolventSyntheticProducure3.ResultsandDiscussionSythesisoftheTriblockCopolymerPrecursorPreparationofParticleNanomaterialPreparationof“SpiderWeb”Nanomterial3.1PreparationofParticleNanomaterialThepreparationofsuperstructurehomogeneoussolution:PSAN-b-PEO-b-PSANselectivesolution：

DMF/toluene(50/50v/v),100mg/mL

spin-coatedonSiwafer

NomicellecouldbedetectedinthesolutionbyPCCS,evenafterincreasingtheconcentrationupto200mg/mL,whichseemstoindicateahighCMCinthissolventsystem.Beyondthisconcentration,thepolymersolutionwastooviscoustobeanalyzed.选择性溶剂DMF，二甲基甲酰胺，极性非质子性溶剂Toluene，甲苯，非极性溶剂Figure2(A).Self-standingnanoparticlesuperlatticefilmpreparedfromaDMF/toluene(50/50,v/v)copolymersolution.AFMtopviewofthesuperstructureandsizedistributionofparticlediameterdeterminedbyapictureanalysisover100particles.Diameter：c.a.50nmNarrowsizedistributionAFMimagea

Large-scaledAFMimageofthenanoparticlefilmtopsurface.b,c

3DAFMimagesshowingthehighregularityinroughnesswithZvalue(21.3nm)closetotheRadius(c.a.25nm)ofonepolymerparticle.AdensepackingofnanoparticlesLarge-scaledAFMimageFigure2(B)SEMtop,bottom,andcrosssectionalviewofastretchednanoparticlefilm.stretchingthefilmcantakeplacewithoutformingcracks.(C)Crackfreestretchednanoparticlefilm.(D)Enlargementofthecross-sectionshowingahomogeneousnanoparticlemorphology.SEMimageThewatercontactangle(WCA)ofthenanoparticlefilmwasmeasuredtobe35°,whichconfirmsthepresenceofhydrophilicPEOontheparticlefilmsurface.ThehydrophobicPSANcoreis“shielded”bythePEOcorona，sothesurfacepropertiesofthematerialisonlyrelatedtothethinPEOlayer.推断

不溶性旳PSAN嵌段：内核（micellarcore）sphericalmicelle可溶旳旳PEO嵌段：核冠（micellarcorona）

AdensepackingofnanoparticlesFilmFormationMechanisim

利用水触角测量仪进行电晕处理聚合物薄膜旳试验措施FormationMechanisimofNanoparticleFilmFigure3.theself-assemblyofPSAN-b-PEOb-PSANintonanoparticlefilmABATriblockCopolymerAftertheappearanceofmicelles,thesolventevaporationleadstoaprogressivedecreaseofthemicelle-to-micelledistance.Whenmicellesarecloseenoughtointeract,dynamicassociationcouldtakeplacethroughbridgedconformationsoftheABApolymerchains，whichleadstopermanentnanomaterials.FirstsolubilizedthecopolymerinDMF(100mg/mL)followedbyaslowadditionofwater.DialyzeremoveDMFInthiscase,micellesweredetectedinPCCSinhighconcentrationwithahydrodynamicdiameterof110nm,whichconfirmstheabilityoftheBCtobeassembledintomicellarmorphology.AnalternativestrategyDMF/waterThisalternativestrategyseemstobelessefficientintermsofparticleorganization.looseDuringthespincoatingofthewater-baseddispersion,micellescomeintocontactwiththesurfaceandstayprobablyataroundthisplacewithoutanyefficientdynamicadjustment.DMF/tolueneDMF/waterLoosenanoparticlefilmDMF/waterItmustbementionedthatnanoparticlefilmscanalsobeobservedfromBCsolutionsinpureDMF.However,thereproducibilitywaspoor.Smallunwantedchangesintheprocessparametersmightswitchtheorganizationfromnanoparticletoshortworm-likesuperstructurepureDMFRepeatedexperimentMixture:Spherical＆Shortworm-likefilmSphericalmicellefilmByaddingsome

toluene,thewindowtotargettheworm-likestructureisenlargedandthereproducibilityisensured.Disconnected

worm-likemicellefilmwithdiameterofabout50nmis

observedbyAFMwhenpuretoluenewasusedassolventAFMtopviewbeforestretchingSEMtopandcross-sectionalviewsafterstretchingFigureS5.Shortdisconnectedworm-likemicellespuretoluenedisconnectedworm-likemicellefilmProcessingisthekeystepandcanalterthequalityofthematerial.ExampleIncreasingthespeedrateofthespincoater,micellesdonothaveenoughtimetoself-organizethroughadynamicprocessandsoroughsurfacewithsomefailurescanbeobserved.FigureS6.AFMimageDMF/toluene(50/50)increasingthespeedrampfrom50to300rpm.s-2.3.2Preparationof“SpiderWeb”NanomaterialAsdiffusitivityofblockcopolymersinsolutionistoosmalltorespondtothefastchangeofsolventconcentrationandcompositionduringtheevaporationstage,theequilibriummicellemorphologyisneverreached.Inthiswork,byincreasingthetoluenecontentfrom50to75vol%,a“spiderweb”superstructurewithahighlyconnectednetworkofworm-likemicellesisobservedinsteadofananoparticlefilm.Theworm-likemicelleshaveadiameterof50nmandtheirconnectionsmakeporeswithanaveragesizeof90nmandabroadporesizedistributionFigure5.Self-standing“spiderweb”superlatticefilmobtainedfromaDMF/toluene(25/75,v/v)copolymersolution.Thetopsurfaceoftheinterconnectedworm-likemicellenetworkAFMimageTheexpected3Dporousnetworkseemsnottobeisotropic,withanorganizationclosetoamultilayersystemwithapreferential2Dconstruction.SEMimageFigure6.SEMcross-sectionalviewofthe“spider-web”nanomaterial.Duringtheevaporationstage,micelleconcentrationincreasesandsomeinterconnectionstakeplacebetweenmicellesthankstothedynamicformationofbridgedconformationoftheABAtriblockcopolymer.YjunctionLarge-scaledAFMimageFigure5.(B)theself-assemblyofPSAN-b-PEO-b-PSANintoa“spiderweb”superstructure.FormingMechanism4.ConclusionsThisstrategyisbasedonthedynamicinteractionsbetweenflower-likemicelles,leadingtoatransitionbetween“loop”and“bridge”conformationsoftheABAchain.Thisbridgeconformationenablestheformationofself-standingcrackfreenanostructuredfilm（无裂缝）Bypla