从超亲水到超疏水(3)

was

14740dx.doi.org/10.1021/am5043627|ACSAppl.Mater.Interfaces2014,6,14736?14743

Figurewhenringaftera8.potential(a)Illustration

applyingofthe+1.5potentialVofwaselectro-wettingappliedof+1.5betweendevice.

Vfor400the(b)

s.(d)waterThe

Thedropletwettability

color(15oftheμL)change

wettingcontaining(inWCA)

ringchanges0.2MofLiClOthePEDOT?P(3-MTH)?lmwithtimeprolonging

from4bluishandthegreen?lm.to(c)reddishFormationbrownofwhenelectro-wettingthereversepotentialof?1.5Visappliedfor10s.

formed.Whenagraduallyreducingpotentialfrom+1.2to?0.2MTH)

VwasappliedtothedopedPEDOT?P(3-MTH),asimilar41moieties.Asaresult,the?lmhasareddishbrowncolor.Upondopingat+1.2V,thePEDOT?P(3-MTH)?lmcurveofWCAversuspotentialwasproduced.Theseshowedared-shiftinitsabsorptionbecauseoftheabsorptionobservationsfurtherindicatedthatthewatercontactangleofchargecarrierbands,41givingrisetoabluishgreencolor.couldbereversiblyregulatedbypreciselycontrollingtheTherefore,thePEDOT?P(3-MTH)?lmexhibitedanelectro-appliedpotential.responsive,switchablewettabilitysurface,thewettabilitystate

3.4.E?ectofElectrolyteonWettabilitySwitching.Toofwhichcouldbeeasilyjudgedbyitscolor.

investigatethee?ectofelectrolyteonthewettabilityofthe3.6.Electro-WettingDevice.Onthebasisoftheelectro-conductive?lm,wealsodopedanddedopedPEDOT?P(3-wettingpropertiesofthePEDOT?P(3-MTH)?lm,weMTH)?lmina0.2MTAHFP/ACNsolution.Itexhibitsadesignedasimpleinsituelectro-wettingdevicetoexplorethesimilarelectrochemicalactivity(Figure6a).Inthiselectrolyteapplicationofsuchaconductivepolymer?lm(Figure8a).44,45solutionsystem,thecounterionPF6?canbeintroducedintoAtthebeginning,awaterdroplet(15μL)containing0.2MthepolythiophenebackbonesunderthedopedpotentialofLiCLO4onthe?lmintheelectro-wettingdeviceexhibitsahigh+1.6V.Di?erentwiththedopantofLiClOcontactanglegreaterthan150°(Figure8b,?rstimage).When

processesahigheroxidation4,thePEDOT?P(3-

MTH)?lmpotentialinthisweappliedthepotentialof+1.5Vbetweenthewaterdropletsystemthanthatin0.2MLiClOandthesuperhydrophobic?lm,thewettabilityofthe?lm

dopedwithTAHFPdid4/ACNsolution.Furthermore,the?lmnotexhibitsuperhydrophi-underneaththewatercontinuouslytransformedfromsuper-licity,buthadasmallWCAofabout15.5°.Uponthepotentialhydrophobicitytohydrophobicity,withtimeprolongingof?0.2Vinthiselectrolytesystem,the?lmcanrecoverits(Figure8b).Ifweignorethee?ectoftheelectrolyteonsuperhydrophobicsurfacewithaWCAofabout155.5°(FigureWCA,webelievethewaterdropletonthis?lmtobeinCassie’s6b).Thus,the?lmintheTAHFP/ACNsolutionsystemonlysuperhydrophobicstate,becausetherewasonlylittleliquid?hasareversiblewettabilityswitchingbetweensuperhydropho-solidcontactareaduetothepresenceofanaircushion.31,32,38bicityandhydrophilicity.ThismaybeduetoamodestWhenapotentialof+1.5Vwasapplied,migrationofthechargehydrophilicityofPF6?.carrier(includinganelectronmovingoutandClO

3.5.PhotoelectricPropertiesandWettability.Thein)ontheliquid?solidcontactlocationoccurred,accompany-4?movingwettabilitytransitionbetweensuperhydrophobicityandsuper-inganelectrochemical(doped)process.Thechangeinthehydrophilicityisaccompaniedbyachangeinthespectralchemicalcomponentontheliquid?solidcontactlocationleadspropertiesofPEDOT?P(3-MTH),asmanifestedinelectro-tothewettabilitychange.Thewaterdropletpermeatedthechromismofthe?lm(Figure7).ThededopedPEDOT?P(3-porous?lmunderpotential(Figure8bandMovieS2,MTH)?lmshowedareddishbrownsurfaceonwhichwaterSupportingInformation).Afterweappliedpotentialfor400dropletswerenearlysphericalinshape(Figure7a).Afters,thewaterdropletonthe?lmhadasmallcontactanglelessdoping,the?lmbecamebluishgreen,andwaterdropletsthan35°(Figure8b,lastimage).Figure8cshowsalargeappliedtothesurfacecouldrapidlyspreadintothe?lm(Figurewettingringafterthevoltagewasappliedfor400s.Inthe7b).Thebluishgreencolorofthedoped?lmdidnotfade,evenwettingring,the?lmexperiencedcompletewetting.Ifweifitwasimmersedinwaterfor10min(FigureS5,Supportingappliedareversepotentialof?1.5Vfor10s,thecoloroftheInformation).ThespectroelectrochemistryofPEDOT?P(3-wettingringchangedfrombluishgreentoreddishbrownMTH)(Figure7c)wasexaminedbyusingaUV/vis(Figure8d).However,itswettabilitystatewasnotrecoveredinspectrophotometercoupledwithanelectrochemicalanalyzer.theacceptablerangeoftime.

Upondedopingat?0.2V,thePEDOT?P(3-MTH)?lmshowedastrongabsorptionmaximumat507nmwithaweak4.CONCLUSION

shoulderpeak,whichcouldbeattributedtotheπ?π*transitionAnelectro-responsiveporousstructuredpolythiophene?lmabsorptionofthethiopheneringsinthePEDOTandP(3-showingreversibleswitchingofwettabilitybetween

super-

14741dx.doi.org/10.1021/am5043627|ACSAppl.Mater.Interfaces2014,6,14736?14743

hydrophobicityandsuperhydrophilicityhasbeensuccessfully(9)Yao,L.;He,J.H.BroadbandAntireflectiveSuperhydrophilicprepared.Thehighlyporouspolythiophene?lm,composedofaThinFilmswithOutstandingMechanicalStabilityonGlassSubstrates.layerofP(3-MTH)appliedtounderlyingPEDOT,wasChin.synthesizedonanITOsubstratebyatwo-stepelectro-(10)J.Tian,Chem.D.2014L.;,32Zhai,,507J.;?512.Song,Y.L.;Jiang,L.Photoelectricdepositionmethod.Thewettabilityswitchingofthis?lmCooperativeInducedWettingonAligned-NanoporeArraysforLiquidbetweensuperhydrophobicityandsuperhydrophilicitycouldbeReprography.Adv.Funct.Mater.2011,21,4519?4526.realizedbyelectrochemicaldopinganddedoping.The(11)Mertaniemi,H.;Jokinen,V.;Sainiemi,L.;Franssila,S.;Marmur,superhydrophobicitywithWCA>150°inthededopedstateA.;Ikkala,O.;Ras,R.H.A.SuperhydrophobicTracksforLow-andsuperhydrophilicitywithWCA≈0°inthedopedstateofFriction,GuidedTransportofWaterDroplets.Adv.Mater.2011,23,thepolythiophene?lmcouldberepeatedlyattainedby2911?2914.alternatelyapplyingpotentialsof?0.2and+1.2V,respectively.(12)Ueda,E.;Levkin,P.A.EmergingApplicationsofSuper-hydrophilic?SuperhydrophobicMicropatterns.Adv.Mater.2013,25,Notably,thewettabilitystatecouldalsobejudgedbythecolor1234ofthe?lm.Asimpledevicewasdesignedforexhibitionofits(13)?Liu,1247.Q.Y.;Gao,L.;Jiang,L.BiomimeticPreparationandMulti-elctro-wettingproperty.Thislarge-areasmartsurfacewithrapidScaleMicrostructuresofNano-Silica/PolyurethaneElastomericFibers.wettabilityswitchingmaypotentiallybeappliedinacademicProg.Nat.Sci.:Mater.Int.2013,23,532?542.and■industrialcontexts.(14)Feng,X.J.;Feng,L.;Jin,M.H.;Zhai,J.;Jiang,L.;Zhu,D.B.ReversibleSuper-HydrophobicitytoSuper-HydrophilicityTransition

ASSOCIATEDCONTENTof(15)AlignedLim,ZnOH.NanorodS.;Han,Films.J.T.;J.Am.Kwak,Chem.D.;Soc.Jin,2004M.,H.;126,Cho,62?63.K.

PhotoreversiblySwitchableSuperhydrophobicSurfacewithErasable

Successive*SupportingInformation

CVcurvesoftheelectrodepositionofP(3-MTH),andPEDOT,andPEDOT?P(3-MTH)?lms;wettabilitychangeof(16)RewritableLim,H.S.;Pattern.Kwak,J.D.;Am.Lee,Chem.D.Y.;Soc.Lee,2006S.G.;,128Cho,,14458K.UV-Driven?14459.P(3-MTH)onITOglass;photographofthedoped?lmReversibleSwitchingofaRoselikeVanadiumOxideFilmbetweenimmersedinwater;andmoviesofthemovingwaterdropletSuperhydrophobicityandSuperhydrophilicity.J.Am.Chem.Soc.2007,andelectro-wettingtest.Thismaterialisavailablefreeofcharge129■viatheInternetathttp://pubs.acs.org.(17),4128Xu,?L.4129.B.;Chen,W.;Mulchandani,A.;Yan,Y.S.Reversible

ConversionofConductingPolymerFilmsfromSuperhydrophobicto

AUTHORINFORMATIONSuperhydrophilic.Angew.Chem.,Int.Ed.2005,44,6009?6012.(18)Xia,F.;Feng,L.;Wang,S.T.;Sun,T.L.;Song,W.L.;Jiang,W.CorrespondingAuthorH.;Jiang,L.Dual-ResponsiveSurfacesthatSwitchbetweenSuper-*E-mail:qhlu@sjtu.edu.cn.hydrophilicityandSuperhydrophobicity.Adv.Mater.2006,18,432?Notes436.(19)Lim,H.S.;Lee,S.G.;Lee,D.H.;Lee,D.Y.;Lee,S.;Cho,K.■Theauthorsdeclarenocompeting?nancialinterest.SuperhydrophobictoSuperhydrophilicWettingTransitionwith

ACKNOWLEDGMENTSProgrammableIon-PairingInteraction.Adv.Mater.2008,20,4438?

4441.

Theauthorsaregratefulfor?nancialsupportfromtheNational(20)Hou,W.X.;Wang,Q.H.UV-DrivenReversibleSwitchingofaScienceFoundationofChina(21374060and51173103),973Polystyrene/TitaniaNanocompositeCoatingbetweenSuperhydro-Projects(2012CB933803and2014CB643605),andthephobicityandSuperhydrophilicity.Langmuir2009,25,6875?6879.NationalScienceFundforDistinguishedYoungScholars(21)Yang,J.;Zhang,Z.Z.;Men,X.H.;Xu,X.H.;Zhu,X.T.ReversibleSuperhydrophobicitytoSuperhydrophilicitySwitchingofa■(50925310).CarbonNanotubeFilmviaAlternationofUVIrradiationandDark