BINDING OF IONIC SURFACTANTS ON OPPOSITELY CHARGED POLYELECTROLYTES OBSERVED BY FLUORESCENCE METHODS

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摘要 Ourrecentstudiesconcerningthebindingofionicsurfactantsonoppositelychargedpolyelectrolytesobservedwithfluorescencetechniquesarereviewed.Thecationicsurfactantscetyltrimethylammoniumbromide(CTAB),dodecyltrimethylammoniumchloride(DTAC),andnonionicsurfactantoctaethyleneglycolmonododecylether(C12E8)wereallowedtobindonanionicpoly(2-acrylamido-2-methylpropanesulfonicacid)(PAMPS)anditspyreneand/ornaphthalenelabeledcopolymers.TherelativeexcimeremissionintensityIE/IMofacationicprobe1-pyrenemethylaminehydrochloridewerechosentomonitorthebindingprocessandtheconformationchangeofsurfactant-boundpolyelectrolytes.The1:1aggregationofpolyelectrolyte-CTABwithrespecttothechargewasfoundaslongastheCTABconcentrationwasslightlyhigherthanitscriticalaggregationconcentration(CAC).TheintermolecularNRETindicatedthattheCTAB-boundpolyelectrolytesaggregatedtogetherthroughthehydrophobicinteractionbetweentheCTABtails.However,neither1:1polyelectrolyte-DTACaggregationnorintermolecularaggregationofDTAC-boundpolyelectrolytewasobservedowingtoitsweakerhydrophobicityof12carbonatomsinthetail,whichisshorterthanthatofCTAB.Asknownfromthefluorescenceresults,nonionicsurfactantC12E8didnotbindontheanionicpolyelectrolytes,butthepresenceofPAMPSpromotedthemicelleformationforC12E8attheCACslightlybelowitscriticalmicelleconcentration(CMC).ThesolidcomplexofdansyllabeledAMPScopolymer-surfactantexhibitedadecreaseinlocalpolaritywithincreasingchargedensityofthepolyelectrolyteorwithalkanetaillengthofthesurfactant.SAXSsuggestedalamellastructurefortheAMPScopolymersurfactantsolidcomplexeswithalongperiodof3.87nmforCTABand3.04nmforDTAC,respectively.
机构地区 不详
出版日期 2003年06月16日(中国期刊网平台首次上网日期,不代表论文的发表时间)
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