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.
