Hydrophobic and Hydrophilic E ff ects in a Mussel-Inspired Citrate- Based Adhesive - Xu, Ji, Ma - 2021 - Unknown

《Hydrophobic and Hydrophilic E ff ects in a Mussel-Inspired Citrate- Based Adhesive - Xu, Ji, Ma - 2021 - Unknown》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

pubs.acs.org/LangmuirArticleHydrophobicandHydrophilicEffectsinaMussel-InspiredCitrate-BasedAdhesiveYiwenXu,YaliJi,*andJinghongMa*CiteThis:Langmuir2021,37,311−321ReadOnlineACCESSMetrics&MoreArticleRecommendations*sıSupportingInformationABSTRACT:Thecitrate-basedtissueadhesive,synthesizedbycitricacid,diol,anddopamine,isakindofmussel-inspiredadhesive.Theadhesionofmussel-inspiredadhesiveisnotcompletelydependenton3,4-dihydroxyphenylalanine(Dopa)groups.Thebackbonestructureoftheadhesivealsogreatlyaffectstheadhesion.Inthisstudy,toexploretheeffectsofhydrophobicityandhydrophilicityofthebackbonestructureonadhesion,wepreparedaseriesofcitrate-basedtissueadhesives(POEC-d)bychangingthemolarratiooftwodiols,1,8-octanediol(O)andpoly(ethyleneoxide)(E),whichformedhydrophobicsegmentunitsandhydrophilicsegmentunits,respectively,inthemoleculestructure.ThepropertiesofcuredadhesivesshowedthattheadhesivewithhighEunitshadhighswelling,rapiddegradation,andlowcohesion.Intheadhesionstrengthmeasurementontheporcineskin,theadhesivewithhigherhydrophobicitywasmorelikelytoperformbetter.Fortheinterfacialadhesion,hydrophilicitywasconducivetothediffusionandpenetrationontheskinsurface,buthydrophobicinteractionshowedastrongereffecttoadherewithskinandhydrophobicassociationincreasedtheadhesiveconcentrationontheinterface;forthebulkcohesion,hydrophobicityledtocoacervation,promotingtheDopa-quinonecouplingforcross-linking.Inthisamphipathic,citrate-based,soft-tissueadhesivesystem,whenthefeedratioofhydrophilicsegmentwaslowerthan0.7,thecoacervationcouldbeformedthroughhydrophobicinteraction,forminganefficientunderwateradhesionsystemsimilartothatofmussels.1.INTRODUCTIONtherebydiminishingthebondingeffectofcatecholand19,20Marinemusselshavedevelopedanaturalmechanismtoformweakeningtheinterfacialadhesion.Meanwhile,otherincrediblystronginterfacialbondstoalmostanykindofsurfacereportsprovedtheintroductionofhydrophilicsegmentsinto1,2DownloadedviaRUTGERSUNIVonMay15,2021at12:32:07(UTC).underwaterthroughbyssus,i.e.,theholdfastofmussels.Thehydrophobicadhesivebackbonecanleadtogoodwettingforbyssuscomprisesdifferentmusselfootproteins(mfp)secretedadhesivecontactandcanalsocontributetothediffusionofbythebondingprocess,andamongthem,mfp-3andmfp-5arewater-solubilitycuringagentinsidetheadhesivestopromotethekeycomponentsoftheplaquethatcontactssurfacesduringmorehomogeneouscross-linking.21,22What’smore,amongour2−8adhesion.StudiesshowedthesetwoproteinshaveanSeehttps://pubs.acs.org/sharingguidelinesforoptionsonhowtolegitimatelysharepublishedarticles.recentlysynthesizedcitrate-basedtissueadhesives,itwasfoundespeciallyhighconcentrationof3,4-dihydroxyphenylalanine9,10thattherewasasignificantdifferenceintheadhesionstrength(Dopa,20−25%inmfp-3and27−30%inmfp-5),andDopawasrecognizedasakeygroupofadhesion.1,9,11ButDopaisnotwhenthehydrophilicsegmentwasintroducedintothereaction12system.23−25However,thereasons,especiallytheeffectofaloneresponsibleforwetadhesion.Thesubsequentstudieshaveconfirmedmultipleinteractionssynergisticallytoformthehydrophilicityandhydrophobicity,havenotbeenstudiedinourentirecomplexbondingmechanismofmussels,suchaspastwork.Here,ourdiscussionisbasedonthemussel-inspiredhydrophobicity,electrostaticincorporation,andπ−cationcitrate-basedadhesivereactionsystemtoidentifytheeffectofbonding(Kimetal.suggesteditcanbetriggeredbyhydrophilicityandhydrophobicityofthecitrate-basedadhesive1,13−15salt).Amongthem,hydrophobicityhasbeendemon-inthebondingprocess.stratedtosignificantlyenhancetheadhesiontosurfaces,particularlyhydrophobicsurfacebyhydrophobicinteraction,andDopacanbenestedinhydrophobicaromaticsequencestoReceived:October2,2020enhanceadhesionatneutralpHcontributingtothecohesiveRevised:December6,2020interactionsbetweenadhesiveproteins.12,16−18ButitalsohasPublished:December22,2020beenproposedthattheinteractionsbetweenhydrophobicchainsandhydrophilicsurfacesarenotfavorable,andthehydrophobicsidechainstendtoavoidhydrophilicsurfaces,©2021AmericanChemicalSocietyhttps://dx.doi.org/10.1021/acs.langmuir.0c02895311Langmuir2021,37,311−321

1Langmuirpubs.acs.org/LangmuirArticleCitricacidhasbeenFDAapprovedandiswidelyusedinTable1.FeedRatios,ReactionTimes,RatiosofHydrophobic24medicine.Thecitric-acid-derivedpolyesterisbiodegradableSegmenttoHydrophilicSegment,andCatecholMassandhasabroadrangeofmechanicalalongwithsurfaceaffinitiesFractionsoftheMussel-InspiredCitrate-BasedPolyester24towardmanycelltypes.Themussel-inspiredcitrate-basedTissueAdhesiveadhesiveispaperedbygraftingdopamineontothepolyestersidecatecholchainbythethirdcarboxylgroupofcitricacid.Thecatecholincitricacid:1,8-massthedopamineisthekeyadhesiongroupofthismussel-inspiredoctanediol:ratiooffractionadhesive.Ourrecentworksynthesizedawater-insolublecitrate-PEO:dopaminereaction−(CH2)8O−and(w/w)abname(molar)time(h)−(CH2CH2O)m−(%)basedadhesive(POC-d)withstrongadhesionstrengthviacitricacid,1,8-octanediol,anddopamineandsynthesizedawater-POC-d1.1:1:0:0.51.51/011.56solubleadhesive(POEC-d)byintroducingthehydrophilicPO0.9EC-d1.1:0.9:0.1:0.539.111.74segment,poly(ethyleneoxide)(PEO),intothereactionPO0.8EC-d1.1:0.8:0.2:0.554.011.74system.24,25Theadhesionstrengthofwater-solublePOEC-dPO0.7EC-d1.1:0.7:0.3:0.573.611.63wasdecreasedcomparedtothewater-insolublePOC-d.ForPO0.6EC-d1.1:0.6:0.4:0.5101.213.35furtherexploringthereasonforthisresult,especiallytofigurePO0.5EC-d1.1:0.5:0.5:0.515.50.913.84outtheeffectofhydrophilicandhydrophobicsegmentsofthePO0.4EC-d1.1:0.4:0.6:0.5190.812.97adhesiveinthebondingprocess,inthisstudy,wepreparedaPO0.3EC-d1.1:0.3:0.7:0.5230.311.28seriesofmussel-inspiredcitrate-basedpolyestertissueadhesivesPO0.2EC-d1.1:0.2:0.8:0.5340.213.18withamphiphilicbackboneandcatecholgrouponsidechainbyPO0.1EC-d1.1:0.1:0.9:0.5440.111.05a1bone-potmeltpolycondensationsofcitricacid(CA),1,8-ThedataobtainedbyHNMRanalysis.Thedataobtainedbyoctanediol(O),poly(ethyleneoxide)(E),anddopamine(DA).UV−Visspectrumanalysis.Weobtained10citrate-basedpolyestertissueadhesiveswithdifferentratiosofhydrophilicsegmentstohydrophobic2.3.PreparationofAdhesiveSolutions.AdhesiveswithsegmentsinthebackbonebychangingthefeedratioofOtodifferenthydrophilicitieswerecompletelydissolvedinthe75%(v/v)ethanolaqueoussolution.Eachgramofadhesivewasdissolvedin3mLEunits,whichrespectivelyprovidehydrophobicandhydrophilicofsolventandmixedtomaketheadhesivesolutionof27.6wt%solidsegmentstructuretoadhesives.Thecontentofcatecholwascontent.keptsimilarinalltheseadhesivesbycontrollingthefeedratioof2.4.WettabilityofAdhesives.AdhesivesolutionsofPO0.1EC-d,DA,sothatwecaneasilyinfertheeffectcausedbyhydrophilicPO0.5EC-d,andPO0.9EC-dweredrippedontopolystyreneplatesandandhydrophobicsegmentsaccordingtothetestresults.gelatin-coatedsubstrates,andthecontactanglesoftheadhesivesolutionswereimmediatelytestedbyacontactanglemeasuringinstrument.2.EXPERIMENTALSECTION2.5.PreparationofCuredAdhesives.Theadhesivesolutionwas2.1.Materials.Citricacid,1,8-octanediol,sodiumperiodatemixedwith10wt%solutionofPIinDMF(volumeratio1:1).The(NaIO4,PI),PEO(Mn=400g/mol),ethanol,fluoresceinmixtureswerethenstirredevenlyandputintoanovenkeptat37°CforisothiocyanateisomerI(FITC),andN,N-dimethylformamide24htofullycross-linkingandfullyremoveofsolvent.Thecuredbulk(DMF)wereallpurchasedfromSinopharmChemicalReagentCo.,adhesivewasobtained.PIisanoxidizingagent,whichtriggersoxidationChina.DopaminehydrochloridewaspurchasedfromSigma-Aldrichandsubsequentlycross-linkingreactionofcatecholuponmixing.Co.,USA.α-Cyanoacrylatemedicaladhesivewaspurchasedfrom2.6.PropertiesofCuredAdhesives.UniaxialtensiletestsofQinhuangdaoKefengMedicalEquipmentCo.,Ltd.AllreagentswerecuredadhesiveswereperformedonaHY941materialtestingmachineusedasreceivedwithoutfurtherpurification.Porcineskinswere(HengyuInstrumentCo.,China)witha100Nsensor.Toinvestigatepurchasedfromalocalsupermarket.themechanicalpropertiesofadhesivesinbothdryandwetconditions,2.2.PreparationofAdhesives.Thecitrate-basedpolyestertissuewepreparedtwokindsofcuredadhesivesamples.Onewaswithoutany23,24adhesivewaspreparedaccordingtoourpreviousreport.Briefly,treatmentaftercuring;anotherwassoakedinPBSphosphatebufferedcitricacid,1,8-octanediol,andPEOwereaddedtoa250mLround-saline(PBS)(pH7.4)for1htobewettedaftercuring.Andthen,thebottomflaskandexposedtoaconstantflowofnitrogengas(Thefeedcuredadhesivesamplewasmadeintothedog-boneshape(narrowestratiosofreactantsareshownintheTable1).Themixturewasmeltedatwidthof2.7mm,gagelengthof20.0mm,andthicknessof0.3mm).160°Cundervigorousstirringandthenaddedwithdopamine.AfterAfterthat,thedog-bone-shapedsampleswerestretchedtofailureatathat,themixturewaskeptstirringat140°Cforaperiodoftimeandtherateof10mm/min.Thetensilemoduliwerecalculatedfromtheinitialreactionwasstoppedjustbeforethegelcriticalpointtocreatestickyslopeofthestress−straincurve(0−5%strainrange).Theresultsofadhesive.Theobtainedadhesivewasfurtherpurifiedbyextensivetensilemodulus,tensilestrength,andelongationatbreakwerethedialysisinDIwaterusing1000-MWCOdialysisbagtocompletelyaverageof5specimens.removetheunreactedreactant,andsubsequentlyophilization.TheTheswellingpropertiesofcuredadhesivesweremeasuredinDIpreparedpurifiedadhesivesweredenotedasPOnEC-d(wheren=feedwater.Theflakesamples(0.2−0.3mminthickness)werewashedbyDIratioof1,8-octanediol).watertoremoveunreactedsodiumperiodate,anddriedtoaconstant24,25Anothercitrate-basedpolyestertissueadhesive,POC-d,wasweight(W1),subsequently,incubatedinDIwater,andthenremovedsynthesizedviaone-potpolycondensationofcitricacid,1,8-octanediolfromDIwateratvarioustimeintervals,gentlywipedwithfilterpapertoanddopaminetocontrastwithPOnEC-d.removeexcessliquidonthesurface,andweighed(W2).TheswellingEveryadhesivewithdifferentfeedratioswastestedby1HNMRpercentageofthesampleswascalculatedusingtheexpression[(W2−spectroscopy(600MHz,DMSO-d6)toconfirmthepercentagesofW1)/W1]100%.Threeindividualexperimentswereperformedandhydrophilicandhydrophobicsegmentsoftheadhesivemolecule.datawereaveraged.Fouriertransforminfrared(FTIR)spectroscopywasusedtoDegradationstudieswereconductedinphosphatebufferedsalinecharacterizethechemicalstructureofPO0.1EC-d,PO0.5EC-d,and(PBS)(pH7.4).Theflakesamples(0.2−0.3mminthickness)werePO0.9EC-d.TheadhesiveswerecastonthesamplestageandmeasuredwashedbyDIwater,driedtoaconstantweight(W1),placedin50mLonaNicolet8700FTIRspectrometerintherangeof600−4000cm−1PBS,andthenincubatedat37°Cforpredeterminedtimepoints.AfterusingATRmode.incubationforpredeterminedtimepoints,sampleswerethoroughlyThecatecholmassfractionoftheadhesivewasdeterminedbyUV−washedwithDIwater,anddriedinanovenat37°Ctoaconstantvisspectroscopyviathestandardcurvemethodatλ=283nm.weight(W2).Themasslosswascalculatedusingequation[(W1−312https://dx.doi.org/10.1021/acs.langmuir.0c02895Langmuir2021,37,311−321

2Langmuirpubs.acs.org/LangmuirArticleFigure1.(A)SchematicrepresentationofPOnEC-dadhesivesthroughpolycondensationreaction.(B)FTIRspectraofPO0.9EC-d,PO0.5EC-d,andPOEC-dadhesives.(C)UV−visspectrumofPOEC-dandPOC-dadhesives.(D)1HNMRspectrumofPOEC-dadhesive.0.1n0.8W2)/W1]100%.Threeindividualtestswereperformedanddataweretemperaturefor24hinthedark,dialyzedfor3dayuntilcompleteaveraged.removalofunreactedFITC,andthenlyophilized.Anadhesivesolution2.7.AdhesionStrengthMeasurement.Theadhesionstrengthsof27.6wt%solidcontent,3%ofwhichwerefluorescentlylabeled,wasweredeterminedbylap-shearstrengthtestsonporcineskinbecauseofthenusedtobondtwopiecesofporcineskinwith10%(w/v)PIitsbiologicalsimilaritytohumandermis.Thefreshporcineskinswereaqueoussolution.Theadhesiveprocesswasthesameasinthepreviouscleanedbyremovalofsubcutaneousfatsandhairs,followedbywashingsectionofadhesionstrengthmeasurement.Afterthat,theskinsamplesusingdetergentunderrunningwater,andthencuttorectangularpieceswerefrozen,sectioned,andstainedwithDAPI.Themorphologyofthe(30mmlong,15mmwide).Theskinpiecesweresoakedin0.01Mtissue−materialinterfacewasobservedunderafluorescencemicro-HCLsolutionfor3mintoensurecompleteremovalofgrease,andthescope(OlympusCorporation,Japan).extraHCLsolutiononthesurfaceofskinwaswipeoffwithfilterpaper.2.9.StatisticalAnalyses.DatawereexpressedasmeansandA50μLadhesivesolutionwasspreadoveranareaof15×15mmofonestandarddeviations(SD).Student’sttestwasusedforstatisticalpiece,anda50μL10%(w/v)PIaqueoussolutionwasspreadontheanalyses,andaPvalueof0.05wasconsideredstatisticallysignificant.secondpiece.Thetwopiecesweresubsequentlybroughtincontactwitheachothertoformacontactareaof15×15mm.Theadhered3.RESULTSANDDISCUSSIONporcineskinswerethencompressedunder100gofweightfor2hinatemperatureandhumiditychamber(30°C,90%RH).Thelap-shear3.1.SynthesisandCharacterizationofPOnEC-dstrengthofbondedskinstripspecimenswassubsequentlymeasuredonAdhesives.ThePOnEC-dwassynthesizedbyafacileonepotaHY-941materialtestingmachine(HengyuInstrumentCo.,China)additive-freemeltpolycondensationof1,8-octanediol(O),witha100Nsensoratacrossheadspeedof5mm/minatroomcitricacid,PEO(E),anddopamineasshowninFigure1A.Tabletemperature.Themaximumload(force)wasdividedbythe1liststhefeedratiosofreactants.ThemoleculeofthePOnEC-doverlappingcontactareaofporcineskinstocalculateadhesionstrength.adhesivehadbothhydrophilicsegment(−(CH2CH2O)m−Exactlythesametestprocedurewasusedforcommerciala-fromEunits)andhydrophobicsegment(−(CH2)8O−fromOcyanoacrylateglue.Testswereperformedatleasttentimesforeachunits).ThechemicalstructuresofPOnEC-dwithdifferentfeedtypeofadhesive,anddatawereaveraged.1ratioswereconfirmedbyFTIR,HNMR,andUV−visInaddition,toexploretheinfluenceofsurfacehydrophilicityandsurfacehydrophobicityonthebondingperformanceofhydrophilicandspectroscopyanalyses(seeFigure1B−D,respectively).hydrophobicadhesives,thelap-shearstrengthtestsofPO0.1EC-dandTheFTIRspectraofPO0.1EC-d,PO0.5EC-dandPO0.9EC-dareshowninFigure1B.Thepeakat∼1520cm−1wasassignedtoPO0.9EC-donbothpolystyreneplatesandcellulosesheetsweredetermined.Theprocedurewasthesameasabove.Testswereamidegroup(−CO−NH−),whichconfirmedtheformationofperformedatleastfivetimesforeachtype,anddatawereaveraged.amidelinkagebetweenthe−COOHgroupsofcitricacidand2.8.InterfaceMorphologyofAdheredPorcineSkin.The−NHgroupsofdopamine.Thestrongpeakat1735cm−12adheredporcineskinwaslyophilized,sliced,andobservedunderanbelongedtocarbonylgroup(CO)stretchingvibrationfromopticalmicroscopetoobservethemorphologyoftheinterfacebetweenesterbond,indicatingtheesterificationreactionoccurredamongtheadhesivesandtissuesurfaces.−1citricacidanddiol.Thepeaksat∼1112cmwereassignedtoTofurtherinvestigatethepermeationbehavioroftheadhesiveinporcineskin,welabeledPOnEC-dadhesivewithfluorescein.PO0.5EC-dthevibrationsof−C−O−Cgroup,implyingtheintroducingofPEOsegments.Thepeaksat∼2872cm−1werethestretchingadhesive(0.35g)wasdissolvedin24.95gof0.01Mphosphatebufferedsaline(PBS),followedbytheadditionof0.0206goffluoresceinvibrationpeakofmethylenegroup.ThebroadpeakscenteredatisothiocyanateisomerI(FITC).Themixturewasstirredatroom∼3458cm−1wereassignedtothehydroxylgroupstretching313https://dx.doi.org/10.1021/acs.langmuir.0c02895Langmuir2021,37,311−321

3Langmuirpubs.acs.org/LangmuirArticleFigure2.(A)ContactangleofPO0.1EC-d,PO0.5EC-d,andPO0.9EC-dadhesivesolutions.(B)PhasebehaviorofthemixtureofPOnEC-dandPIaqueoussolution.(C)Microscopyimageofcoacervatesformedbyhighhydrophobicadhesivesolution(yellow)andPIaqueoussolution(gray)(PO0.6EC-dwasselectedasatypicaltodisplayinthepicture).vibration.Alltheadhesiveswithdifferentfeedratiosweretestedchainsandhydrophilicsurfacesarenotfavorable,andtheby1HNMR(FigureS1).The1HNMRspectrumofPOEC-dhydrophobicsidechainstendstoavoidhydrophilicsurfaces,0.8wasshownintheFigure1D.Thepeakassignmentsarelistedwhichwillreducethebondingstrengthonhydrophilic19,20below:1.26ppm,from−CH2−ofOunitsintheadhesivesurfaces.Therefore,weexploredthewettabilityofthesemolecule,markedaandb;1.53ppm,from−CH2−ofOunits,amphiphilicadhesiveswithbothhydrophilicsurfaceandmarkedc;3.5ppm,from−OCH2−ofEunits,markedh,andhydrophilicsurface.Inordertomakealltheadhesiveswithfrom−OCH2−ofOunits,markedd;2.5−3.0ppm,fromdifferenthydrophilicitycompletelydissolved,wechose75%(v/−CH2−ofcitricacidanddopamine;6.2−6.7ppm,fromphenylv)ethanolaqueoussolution,whichisacommonmedicalgroupofdopamine.disinfectantassolvent.TheimagesofPOnEC-dandPOC-dThepeakpositionsofalltheinfraredspectrumandallthe1HadhesivessolutionareshowninFigureS2.ThecontactanglesofNMRspectrumarebasicallythesame,whichindicatesthethreemosttypicaladhesivesolutions,PO0.1EC-d,PO0.5EC-d,chemicalstructuresofPOnEC-dwithdifferentfeedratiosareandPO0.9EC-d,werechosentoshowintheFigure2A.basicallythesame.Thepolystyrene(PS)isapolymerwithoutanyhydrophilicThecatecholgroupisthekeygroupthatplaystheroleofgroupandthesurfaceofPSplateishighlyhydrophobic.Onthe9,11adhesion.Thus,thecatecholmassfractionofallthePSplate,thecontactanglefollowedtheorderPO0.9EC-d

4Langmuirpubs.acs.org/LangmuirArticle0.7wereconsideredhydrophobicadhesives,andPO0.1EC-d,PO0.2EC-d,andPO0.3EC-dwereconsideredhighhydrophilicadhesives.Tofurtherunderstandthephasebehaviorofcoacervatesinthecuringprocessofadhesivewithdifferentcontentofhydrophobicsegments,wedroppedthePOnEC-dadhesivesolutionontotheglassslide,covereditwithcoverglass,andobserveditunderanopticalmicroscope.TenweightpercentPIaqueoussolutionwasdroppedontheonesideofthecoverglasstoobservetheinitialstageofcuringprocess.AsshowninFigure2C,atthemomentofthePIsolutioncameintocontactwiththesolutionofadhesiveswiththefeedratioofPEOlowthan0.7,theliquid−liquidseparationappearedimmediately.AsthePIaqueoussolutiondiffusedintotheadhesivesolution,twoFigure3.SwellingratiosofcuredadhesivesinDIwater.solutionscouldnotcompletelymiscibleandtheexcesswaterwassqueezedoutbythehydrophobicinteractionfromthehydrophobicsegment,formingtherounddropletsintheFigureadhesivestomechanicallymatchsofttissuesforbetterload2C.Atthesametime,catecholgroupsintheadhesivewerebearingandstresstransferring.24TheresultsofelongationatcontinuouslyoxidizedbysodiumperiodateandDopa-quinone-break,tensilemodulus,andtensilestressareshowninFigure4.couplingoccurred.TheadhesivegraduallysolidifiedandlostIntheresultofthecuredadhesivesindrycondition(Figurefluidity.Astotheadhesivewithhighhydrophilicsegments4A,C,E),comparedwithPOC-d,whenasmallamountofPEOcontent,whenthefeedratioofPEOover0.6,i.e.,PO0.3EC-d,wasintroducedintothereactionsystem,theelongationatbreakPO0.2EC-d,andPO0.1EC-d,itcouldbecompletelymisciblewithofPO0.9EC-dobviouslyincreased(p<0.05),thetensilePIsolution,andcouldnotsolidifyinashorttime.Thus,themodulussharplydecreased(p<0.05),butthetensilestrengthadhesivedissolvedintheliquidwouldeasilyflowoutofthedecreasedalittle(p<0.05).ThepresenceofPEOsegmentinbondingarea,resultinginalossofadhesives.Theadhesivewiththestructuremadethecuredadhesivesmoreelastic.24AsmoremorehydrophobicsegmentshasstrongerhydrophobicandmorePEOwereintroducedintothereactionsystem,theinteraction,sothattheliquid−liquidseparationphenomenonelongationatbreakdecreasedinitiallyandincreasedafterward,wasfasterandmoreobvious,whichmeansmorewatercouldbewhereasthetensilemodulusandthetensilestrengthincreasedcrowdedoutinashorttime,makingthefluidityoftheremainingfirstandthendecreased.Theadhesivewasthestrongestandadhesivedecreasemorerapidly.Therapidsolidifyingcouldhardestwhenthefeedratioof1,8-octanedioltoPEOwasclose.reducethelossofadhesives,makingtheoperationsimpleandInotherwords,thebulkcohesioncapacityofcuredadhesivesinefficientinpracticalapplication.dryconditionwasthelargestwhenthecontentofhydrophilicTomakethesamplewithacertainshapeforthepropertytest,segmentwasclosetohydrophobicsegmentintheadhesivethesolutionofPIinDMFwasselectedinthepreparationofmolecule.23,26Thispossiblyduetothefactthatduringthecuredadhesivestoslowdownthehydrophobicassociationssolidification,thehydrophobicadhesive(thefeedratioofEunitscausedbythechangeinsolventatthebeginningofmixing.The<0.7)couldformacoacervatebyhydrophobicinteractionandcoacervationinhydrophobicadhesivesolutionswouldstillthesimultaneouscross-linkingofcatecholresultedintheoccurduringthecuringprocessinducedbytheriseofwaterformationofcuredadhesives;however,theexcessivehydro-componentinthesolventcausedbyrapidvolatilizationofthephobicityhinderedthediffusionofPIintothecoacervate,ethanolinthemixture,whichpromotedintermolecularcausinginsufficientcross-linking,whereasexcessivehydro-interactionsovertheinteractionofhydrophobicadhesivephilicityreducedthehydrophobicinteractionandthusmoleculewithsolvent.Therefore,webelievethatthecuringdecreasedthecohesion.processofhydrophobicadhesivesinthepreparationofcuredIntheresultofthecuredadhesivesinwetcondition(FigureadhesiveswasstillthroughthecoacervationandDopa-quinone-4B,D,F),thetensilemodulusandthetensilestrengthofallthecoupling,whichwasconsistentwiththecuringprocesswhensamplewereobviouslydecreasedduetotheswellingoftheusingPIaqueoussolution.adhesivestructure.Differentfromtheresultoftheadhesivesin3.4.PropertiesofCuredAdhesives.Theswellingratiosofdrycondition,comparedPO0.9EC-dtoPOC-d,thetensilethecuredadhesivesweretestedasshowninFigure3.WiththemodulusshowednosignificantdifferenceandthetensileincreaseinthefeedratioofPEO,theproportionofhydrophilicstrengthincreasedalittle(p<0.05),whichmeansthesegmentalsoincreases,andtheswellingrateinevitablyincreases.introductionofasmallnumberofhydrophilicsegmentsreducesTheequilibriumswellingofthecuredadhesive,withthePEOtheinfluenceofwettingonmechanicalproperties.Asthefeedfeedratiobelow0.8,wasachievedin1day,whereasPO0.1EC-dratioofPEOincreased,therewasnosignificantdifferenceintheandPO0.2EC-dneeded3days.TheresultsshowedthatPOC-dtensilemodulusofPO0.9EC-d,PO0.8EC-d,PO0.7EC-d,PO0.6EC-demonstratedalowswellingratioof5.7%andtheswellingratiod,andPO0.5EC-d.Onlywhenthefeedratioof1,8-octanediolsignificantlyincreased,rangingfrom11.7to123.7%,asthewaslowerthan0.3,i.e.,PO0.2EC-dandPO0.1EC-d,thetwohydrophilicsegmentfromPEOwasintroduced.adhesiveswiththelargestproportionofhydrophilicsegments,Theuniaxialtensiletestswereperformedforthecuredthetensilemodulusdecreasedobviouslybecauseofhighadhesivestofigureouttheirbulkcohesioncapacity.Thestress−swelling.straincurvesareshowninFigureS3.ItwasclearthatalltheTosumup,appropriateratiosofhydrophilicsegmenttocurvesofadhesivesindryandwetconditionsdemonstratedahydrophobicsegmentareconducivetosufficientcross-linking,rubberlikebehaviorsimilartoatypicalstress−straincurveofbutswellingwillreducetheload-bearingcapacityoftheelastomer,whichwasespeciallyimportantforsofttissuestructure,sothatadhesiveswithdifferentratiosofhydrophilic315https://dx.doi.org/10.1021/acs.langmuir.0c02895Langmuir2021,37,311−321

5Langmuirpubs.acs.org/LangmuirArticleFigure4.Mechanicalpropertyofthecuredadhesivesin(A,C,E)dryand(B,E,F)wetconditionsfromtheuniaxialtensiletests.Figure5.WeightlossofcuredadhesivesinPBS.segmenttohydrophobicsegmenthadlittledifferenceinhydrophilicsegmentshowedthelowerthemassloss,i.e.lowercohesionunderthewetstateexceptPO0.2EC-dandPO0.1EC-d.degradationrate.ThiswasbecausewiththeintroductionofThemasslosscurveisshowninFigure5todescribethehydrophilicsegment,thecross-linkingofcatecholinthecureddegradationpropertiesoftheadhesive.Themasslossfromadhesivewasmoresufficient,andthehighcross-linkingdegreePO0.9EC-dtoPO0.6EC-dafter7weekswerefrom56.17tomadethebulkadhesivehardanddifficulttodegrade.Asshown31.60%(Figure5A),andtheadhesivewithhigherproportionofinFigure5B,PO0.1EC-d,PO0.2EC-dandPO0.3EC-dwere316https://dx.doi.org/10.1021/acs.langmuir.0c02895Langmuir2021,37,311−321

6Langmuirpubs.acs.org/LangmuirArticleFigure6.(A)Lap-shearadhesionstrengthdatausingwetporcineskinsasadherendandtheimagesofmeasurementsetup.(B)ShearadhesionstrengthofPO0.1EC-dandPO0.9EC-donthePSplateandcellulosefilm.(C)Fluorescencemicroscopicimageoflongitudinalsectionofadheredarea.ThecellnucleuswasstainedwithDAPI(blue)andadhesivewasstainedwithfluorescein(green).completelydegradedin3,4,and5weeks,respectively,andsegmentsresultsinthelowestbondstrength(16.6kPa),PO0.4EC-dbegantodegradeinlargequantitiesatthesixthweek,whichcouldstillbecomparabletocommercialfibringlue,whose33,34andthemasslossofPO0.4EC-dandPO0.5EC-dafter7weeksadhesionstrengthwasreportedintherangeof9−15kPa.were72.46and35.81%,i.e.,theadhesivewithhigherproportionThereisaconsensusthatthemacroscopicadhesionofhydrophilicsegmentsshowedthehigherdegradationrate,performanceforcatechol-basedtissueadhesivesdependsonandthedegradationofhighhydrophilicadhesive,PO0.1EC-d,bothinterfacialadhesionabilityandbulkcohesionability;PO0.2EC-d,andPO0.3EC-d,wassignificantlyfasterthanthatofinterfacialadhesionresultsfromthecovalentbondingofhighhydrophobicadhesive,PO0.9EC-d,PO0.8EC-d,andcatecholandorganicsurfacesandbulkcohesionoriginates7,23,26PO0.7EC-d.Thereasonwasthattheswellingincreasesrapidlyfromcatechol-relatedpolymerizationorcross-linking.Itwiththeincreaseinhydrophilicsegments.Meanwhile,becausewasdiscussedintheuniaxialtensileteststhatadhesiveswiththecitrate-basedpolyesteradhesivedegradesmainlythroughdifferentratiosofhydrophilicsegmenttohydrophobicsegmenthydrolysisofesterlinkages,ahighproportionofhydrophilichadlittledifferenceincohesionunderwetstateexceptPO0.2EC-segmentsmeansgreaterwateruptake,resultinginfasterdandPO0.1EC-d.Therefore,interfaceadhesionstrengthmightdegradation.Moreover,theoligomerproducedbydegradationbethekeytotheadhesionstrengthtrend.Fortheinterfaceofadhesivewithbetterhydrophilicitywaseasierdissolvedinadhesion,itcouldbedividedintotwostages:first,theadhesivewater,whichcontributedtothemassloss.Inaddition,POC-dmoleculewasclosetothesurfaceandformedaweakreversiblehadthelowerdegradationratethanPO0.9EC-d(Figure5)wasadhesion,thenPIcameinandthecatecholnearthesurfacewasbecausethelackofhydrophilicPEOsegmentwouldhindertheoxidized,andMichaeladditionreactionoccurredwiththediffusionofPI,resultinginlowcross-linkingdegree,butattheaminogrouponthetissue,formingastrongdurableadhesionatsametime,thebulkadhesiveshowedaveryhighhydrophobicitylast.Gettingmorecatechol-containingadhesivemoleculestothetopreventthewaterfromentering.surfacewasthekeyinordertoeventuallyformmorechemical3.5.AdhesionStrength.Thefreshporcineskinwasusedasbonds.Inthecaseofthesameadhesivearea,itcouldbedividedadherendintheadhesionstrengthtest,duetoitsbiologicalintotwoaspectstomakemoreadhesivemoleculesadsorbedonsimilaritytohumandermisandcommonlyusedforbiomedicalthesurface:adhesiveforce(i.e.,theinteractionbetweenthe23,27−29experiments.Theresultsofadhesionstrengthandtheadhesivemoleculesandthesurface)andtheadhesivetypicaladhesiontestsetuparedemonstratedinFigure6A.Theconcentrationontheinterface.strongcommercialcyanoacrylateadhesive,whichiswidelyused,Fortheadhesiveforce,themechanismofadhesivemolecules30−32wasusedasacontrast.Amongthecitrate-basedpolyesteradheredtohydrophilicandhydrophobicsurfaceswasdifferent:tissueadhesiveweprepared,POC-d(freeofPEO)behavedbesttheadhesiveadheredtothecompletelyhydrophobicsurfaceandshowedmorethanhalftheaverageadhesionstrengthofthethroughhydrophobicinteraction,whereasitadheredtothe12strongestcommercialadhesive,cyanoacrylate.Withthecompletelyhydrophilicsurfacethroughhydrogenbonds.SkinintroduceofhydrophilicsegmentfromPEO,theadhesionisasurfacewithgoodhydrophilicity,butalsocontainsasmallstrengthdecreased.Andtheadhesionstrengthwaspositivelyamountofhydrophobicaminoacidresiduesandfattyacids,socorrelatedwiththeproportionofhydrophobicsegmentinthetheamphiphilicadhesivemoleculescouldpushasidethewateradhesivemolecule.Thehighestproportionofhydrophilicmoleculesonthesurfacetoadheretotheskinthroughboth317https://dx.doi.org/10.1021/acs.langmuir.0c02895Langmuir2021,37,311−321

7Langmuirpubs.acs.org/LangmuirArticleFigure7.Longitudinalsectionofadheredareaonfreeze-driedporcineskinandthecuredadhesivetornfromthemiddleoftheadheredporcineskins(T=tissue,I=interface).35hydrogenbondsandhydrophobicinteraction.However,theareaofbluedotsappearedgreen,implyingthishighhydrophilicadhesioninteractionenergyofthehydrophobicinteractionadhesivecouldeasilydiffuseandpermeateintotheskin.This(range=−4to−9mJ/m2)wasfargreaterthanthatoftheindicatedthatthehydrophilicsegmentpromotedtheaffinity212hydrogenbonds(≤−0.5mJ/m).Therefore,theadhesivebetweenadhesivesandskintissuebutledtoalowadhesiveforceontheskinmainlydependedonthestrengthofconcentrationontheinterface.Theadhesivewithhigherhydrophobicinteraction.Theadhesivewithhigherhydro-hydrophobicityhadstrongerhydrophobicassociation,makingitphobicitycouldformstrongerhydrophobicinteractionwithskinmoretendtoformcoacervatestoaggregateadhesivemolecules,surface,resultinginthestrongerinterfaceadhesionstrength.andthusincreasedtheinterfaceadhesionstrength.Toverifythedifferentinteractionsofhydrophilic/hydro-Tosumup,theadhesivewithhigherhydrophobicitytendedphobicadhesivesonthehighhydrophilic/hydrophobicsurfaces,tohavestrongeradhesiveforceandformcoacervatestoachievewedeterminedthelap-shearstrengthtestsofhighhydrophilicahighconcentrationofadhesivemoleculesontheinterface.PO0.1EC-dandhighhydrophobicPO0.9EC-donbothBothoftheseresultedinthestrongerinterfaceadhesionpolystyreneplatesandcellulosesheets.ThePSplateishighlystrength,thusformingthestrongermacroscopicadhesionhydrophobic.Andcellulosesheetswereusedasahydrophilicstrength.Inaddition,electrostaticincorporationanddispersionsurfaceduetoitsmoleculescontainalargenumberofforceshavealsobeenreportedtobeeffectiveintheinterface35,36hydrophilicgroups.AsshowninFigure6B,PO0.1EC-dadhesion.Becausetheunchargeddiolwastheonlychangeperformedmuchbetteronhydrophilicsurface,whereasintheseadhesivemolecules,theseeffectswouldnotbethemainPO0.9EC-dperformedmuchbetteronhydrophobicsurface;influencingfactorsofadhesionstrengthhere.moreover,onthehydrophilicsurface,theshearadhesionIntheabove,weinferredthestrengthofinterfacialadhesionstrengthofPO0.1EC-dwassignificantlyhigherthanthatofthroughtheinterfaceinteractionandtheadhesiveconcentrationPO0.9EC-d(p<0.05),whereasonthehydrophobicsurface,theontheinterface,tointuitivelyunderstandthestrengthofshearadhesionstrengthofPO0.9EC-dwassignificantlyhigherinterfacialadhesion,thesectionofadheredporcineskinwasthanthatofPO0.1EC-d(p<0.05).Thisindicatedthatadhesivestudied.withhighhydrophilicitytendedtoformhigherinterfacialTheinterfacialmorphologybetweentwoadheredporcineadhesionstrengthwiththehydrophilicsurface,whereasskinsvariedwiththehydrophobicity/hydrophilicityofadhesives37adhesivewithhighhydrophobicitytendedtoformhigher(Figure7),andreflectedtheinterfacialadhesionstrength.Forinterfacialadhesionstrengthwiththehydrophobicsurface.OnPO0.9EC-d,twopiecesofskinwerecloselyadheredwitheachthehighhydrophobicsurface,theadhesivewithhighhydro-other,whereasforPO0.1EC-d,theadheredporcineskinscouldphobicityhadthestrongerhydrophobicinteraction;onthehighnotkeepadhesionafterfreeze-drying(Figure7(top)).Duetohydrophilicsurface,theadhesivewithhighhydrophilicitycouldtheincreaseofhydrophilicitywouldincreasethewateruptake,formmoreabundanthydrogenbonds,leadingtothestrongerthebondingareawouldbeexpandedandbecomemoreporousinterfaceinteraction.Theseresultsprovidesomeadvicefortheandlooser.Andthus,thehighhydrophobicbondingareawasselectionofadhesivesfordifferenttissues.morecompactandcontinuous,whichmeansastrongerinterfaceAsfortheadhesiveconcentrationontheinterface,theadhesion.Itcanbeclearlyseenthatthehighhydrophilicmorphologyofthetissue−material−tissueinterfacewasPO0.1EC-d(orangeyellow)canpenetrateintothetissuetoformobservedunderafluorescencemicroscope(Figure6C).Theadeepadhesivelayer,butthebearingcapacitywasinsufficientareawiththebluedotswastheareaofporcineskin.PO0.9EC-dduetothehighswellingandlowcohesion.Thecuredadhesive(green)hadaclearoutline,implyingthecoacervationinthiswastornfromthemiddleoftheadheredporcineskinstobehighhydrophobicadhesive,whichmeantahighconcentrationvisuallyobservedtheinterfacialadhesionstrengthbyfragmentsofadhesivemoleculesontheinterface.ForthePO0.1EC-d,theoftissueleftontheadhesive.AsshowninFigure7(bottom),all318https://dx.doi.org/10.1021/acs.langmuir.0c02895Langmuir2021,37,311−321

8Langmuirpubs.acs.org/LangmuirArticleFigure8.Imageofthemixtureofadhesivesolutionand10wt%PIaqueoussolution(volumeratio1:1)onslideandporcineskin.Figure9.Proposedcartoonmechanismforadhesionofhighhydrophilicadhesives(thefeedratioofPEO>0.6)andhydrophobicadhesives(thefeedratioofPEO<0.7).thecuredadhesivewasstillfirmlyattachedwithsometissueweightduringthecuringprocess.Thecolorofcatecholwouldfragments.PO0.9EC-dwascompletelywrappedinthetissue,turnbrownafteroxidizedtoquinones,andboththeMichaelmeaningthestrongestinterfacialadhesion.PO0.5EC-dwasadditionreactionbetweenadhesivesandthesurfaceandthesecond.Thisverifiedtheanalysisoftheinterfaceadhesioninthecross-linkingbetweentheadhesivemoleculescanonlytakeabove.placeaftertheoxidationofcatechol,sothereactiondegreeofthe3.6.AdhesionMechanismofAdhesiveswithDifferentadhesivecanbejudgedbyobservingthecolordepth.FortheHydrophilicity/Hydrophobicity.Inordertofurtherexploreinterfacialadhesionofcatecholandporcineskin(Figure8),thedifferentadhesionmechanismofhydrophilicadhesivesandbothPO0.1EC-dandPO0.9EC-dcouldmakeporcineskinbrownhydrophobicadhesives,weobservedtheinitialstateoftheaftercuring,indicatingthatalltheadhesivewepreparedcouldcuringprocessunderamicroscope,andthecuringstateafter1hinteractwithskinwellbytheMichaeladditionbetweensurfacewasalsoobserved.aminesandcatechol.Forintermolecularcuring(Figure8),Theadhesivesolutionand10wt%PIaqueoussolution(volumeratio1:1)weremixedonaglassslideandapieceofPO0.9EC-dsolutioncouldimmediatelystartedcoacervationinporcineskin,andthenthemixturewascuredinthetemperaturethepresenceofthePIaqueoussolution,andaftercuringfor1handhumiditychamber(30°C,90%RH)for1htoobservetheonglasses,onwhichthequinonewasonlyinvolvedinDopa-degreeofreactions.Themixtureontheporcineskinwasquinonecoupling,wecanseethatthecolorofPO0.9EC-dwascoveredwithcoverglassesandcompressedunder100gofsignificantlydarkerthanthatofPO0.1EC-d,implyingthat319https://dx.doi.org/10.1021/acs.langmuir.0c02895Langmuir2021,37,311−321

9Langmuirpubs.acs.org/LangmuirArticlecoacervationpromotedcross-linkingduetothemolecularthewetstate,exceptPO0.1EC-dandPO0.2EC-d.FromPO0.9EC-aggregatedbyhydrophobicinteraction.dtoPO0.6EC-d,thedegradationrateofadhesivedecreasedwithAsisknown,musselssecreteadhesiveproteinsinacoacervate,theincreaseinhydrophilicsegmentratioduotothecross-2,14whichformedthroughmultipleintermolecularinteractions;linkingdegreeofDopa-quinone-coupling;fromPO0.5EC-dtothecoacervatehaslowinterfacialenergyandahighdiffusionPO0.1EC-d,adhesivewithahigherproportionofhydrophilic2coefficient,enablingefficientwettingontheadheredsurfaces;segmentshowedthehigherdegradationrateduetotheswelling.theproteinhasagoodrheologicalpropertyatthebeginningtoTheadhesivestrengthofhigherhydrophobicadhesivespreadoverandclosetothesurface,andthenitenterscuringperformedbetterontheporcineskin.Forinterfacialadhesion,38processbecominghard.Fromtheanalysisoftheabovehydrophilicitywasconducivetothediffusionandpenetrationonmeasurementsandinspiredbythemusseladhesionsystem,weskinsurface,buthydrophobicinteractionandcoacervationsummarizedtheadhesionmechanismonporcineskinfortheshowedastrongereffecttoadherewithskin.Forbulkcohesion,mussel-inspiredcitrate-basedadhesivewithdifferenthydro-thehydrophobicadhesive(thefeedratioofPEO<0.7)couldphobicity/hydrophilicity.Forhydrophobicadhesives,attheformcoacervationthroughhydrophobicinteractiontopromotebeginningofbonding,theadhesivemoleculegotclosetothetheDopa-quinone-coupling,whereasthehighhydrophilicsurfaceandformedaweakreversibleadhesionbyhydrophobicadhesive(thefeedratioofPEO>0.6)withnocoacervationinteractionandhydrogenbonds,andwiththemixingofPIcouldonlyslowlycuredbyDopa-quinone-coupling.Thus,theaqueoussolution,viscouscoacervates,similartothemusselhydrophobicityinthemussel-inspiredcitrate-basedadhesivebondingsystem,wereformedthroughthehydrophobicleadstostrongerinterfacialadhesionandbulkcohesion,associationofhydrophobicsegments,whichcouldaggregateresultinginthehigheradhesionstrength.Overall,theadhesivemoleculestoimprovetheadhesiveconcentrationonamphipathiccitrate-basedsoft-tissueadhesivewiththefeedtheinterfaceandpromotecross-linking.Atthesametime,theratioofPEO<0.7showedanefficientunderwateradhesioncatecholgroupwasgraduallyoxidized,followedbyMichaelsystem,anditcangivesomesuggestionstodesignnewmussel-additionwiththeaminogrouponthetissueforminginterfacialinspiredadhesivesformedicalapplications,thoughmoreadhesion,Dopa-quinone-couplinginthecoacervatemakingtheresearchoftheadhesivemechanismatthemolecularleveliscoacervateahardsolid,andDopa-quinone-couplingintheneeded.liquidandonthesurfaceofcoacervatemakingthesolidpartsfinallyconnecttogethertoformthebulkcohesionbetweentwo■ASSOCIATEDCONTENTskins.Thehydrophilicsegmentenabledefficientwettingand*sıSupportingInformationinfiltratingtothesurfaceofporcineskin.Finally,twopiecesofTheSupportingInformationisavailablefreeofchargeattissuewerebondedtogetherbybothinterfacialadhesionandhttps://pubs.acs.org/doi/10.1021/acs.langmuir.0c02895.bulkcohesion.Enoughhydrophobicitywasessentialbothinthe1HNMRspectrumofPOEC-dandPOC-d;imagesofinterfacialadhesionandcohesionformationtopromoteannefficientandstrongbonding.ThehighhydrophilicadhesivePOnEC-dandPOC-dadhesivesolution;stress−straincouldnotextrudewaterformingcoacervatesandadheretothecurves(PDF)surfacethroughhydrophobicinteraction,leadingtothelowefficiencyofcross-linkingandinterfacialadhesion.The■proposedcartoonmechanismisdepictedinFigure9.AUTHORINFORMATIONCorrespondingAuthors4.CONCLUSIONSYaliJi−StateKeyLaboratoryforModificationofChemicalFibersandPolymerMaterials,CollegeofMaterialScienceandTheroleofhydrophilicsegmentsandhydrophobicsegmentsinEngineering,DonghuaUniversity,Shanghai201620,China;themussel-inspiredcitrate-basedsoft-tissueadhesivewereorcid.org/0000-0003-2316-5388;Email:jiyali@studied.Aseriesofcitrate-basedpolyestertissueadhesivesdhu.edu.cnwithvariousratiosofhydrophilicsegmentstohydrophobicJinghongMa−StateKeyLaboratoryforModificationofsegmentswassuccessfullypreparedbychangingthefeedratioofChemicalFibersandPolymerMaterials,CollegeofMaterialtwodiolswhich,respectively,providehydrophilicandhydro-ScienceandEngineering,DonghuaUniversity,Shanghaiphobicsegmenttotheadhesivemoleculestructure.Through201620,China;Email:mjh68@dhu.edu.cnultravioletabsorbanceanalysis,ithasbeenconfirmedthatthecatecholgroupcontentofPOnEC-dadhesivewithdifferentfeedAuthorratiowassimilar.ThecontactangletestshowstheadhesiveYiwenXu−StateKeyLaboratoryforModificationofChemicalsolutionwithhigherpercentageofhydrophilicandhydrophobicFibersandPolymerMaterials,CollegeofMaterialScienceandsegmentshadthelowercontactangleonhydrophilicsurfaceandEngineering,DonghuaUniversity,Shanghai201620,China;hydrophobicsurfacerespectively,indicatingthehydrophilicorcid.org/0000-0001-8394-3861segmentcontributestodiffusionandwettabilityoftheadhesiveCompletecontactinformationisavailableat:toporcineskin.ThePOnEC-dsolutionwiththefeedratioofEhttps://pubs.acs.org/10.1021/acs.langmuir.0c02895unitslessthan0.7immediatelystartedcoacervationwhenthevolumeratioofadhesivesolutionstoPIaqueoussolutionwasNotes1:1.TheadhesivebulkcohesionindryconditionaftercuringTheauthorsdeclarenocompetingfinancialinterest.showedthattheappropriateratiosofhydrophilicsegmenttohydrophobicsegmentwereconducivetosufficientcross-linking.Buttheadhesivebulkcohesioninwetconditionshowedthat■ACKNOWLEDGMENTSswellingdestroyedtheload-bearingcapacityofthestructure,Thisworkwassupportedby“theFundamentalResearchFundsandmostadhesiveswithdifferentratiosofhydrophilicsegmentfortheCentralUniversitiesandGraduateStudentInnovationtohydrophobicsegmenthadlittledifferenceincohesionunderFundofDonghuaUniversity”(GrantCUSF-DH-D-2019015).320https://dx.doi.org/10.1021/acs.langmuir.0c02895Langmuir2021,37,311−321

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