Surfactant self-assembly kinetics and thermodynamics of micellar and microemulsion systems

231 Pages·1996·7.2 MB·English

by  Huibers, Paul D.T.

SURFACTANTSELF-ASSEMBLY,
KINETICSANDTHERMODYNAMICSOF
MICELLARANDMICROEMULSIONSYSTEMS
By
PAULD.T.HUIBERS
ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOL
OFTHEUNIVERSITYOFFLORIDAINPARTIALFULFILLMENT
OFTHEREQUIREMENTSFORTHEDEGREEOF
DOCTOROFPHILOSOPHY
UNIVERSITYOFFLORIDA
1996
Copyright1996
by
PaulD.T.Huibers
Idedicatethisdissertationtomyparents,ElizabethC.andDerkT.A.Huibers,for
withouttheirguidanceandconstantsupportIwouldnothavegivenupmyjob,gonebackto
school,andembarkedonasecondcareer.
ACKNOWLEDGMENTS
SeveralorganizationsandpeoplehavehelpedmeduringmyPh.D.research.Iwould
liketoacknowledgethefinancialsupportofKraftGeneralFoodsandICIAmericasInc.for
researchfunding,andICISurfactantsandRhone-Poulencforsurfactantdonations.Ihave
benefitedfrominteractionswithotherdepartments,andwouldspecificallyliketothankDr.
RandolphDuranforuseofhisLangmuirtroughequipment, andDr. WallaceBreyfor
assistance in running NMR samples on surfactants. Many thanks go to Dr. Alan R.
KatritzkyandhisQSPRgroup,especiallyDr.MatiKarelsonandDr.VictorLobanov,as
oursuccessfulcollaborationoverthelastyearandahalfhasledtooneofthethreechapters
inthisthesis,andseveralpapers.Iwouldliketothankthegraduatestudentswhohave
graduatedbeforeme,andtaughtmealotaboutinterfacialphenomena:Dr.Seong-GeunOh,
Dr.VinodPillai,Dr.PromodKumar,Dr.S.Hingorani,Dr.CP.Singh,andDr.Y.K.Rao.I
wouldliketothankMerleReginoforherhelpandsupportthroughmyPh.D.program.
SpecialthanksgotothelateDr.N.M.vanOsforhishelpandtoDr.ChristianReichardtfor
hisadviceonsolvatochromismandhisinvitationtometospeakatPhillipsUniversityin
Marburg,Germany.Finally,Iwouldliketoacknowledgemyadvisor.Dr.DineshO.Shah,
forhisguidanceandinspirationthroughthesepastfouryears.Hisadvicehasledmeon
manyfruitfulresearchpaths,andhissponsorshiphasallowedmepursueinterdisciplinary
projectsandtopresentmyworkatseveralnationalandinternationalmeetings.
iv
TABLEOFCONTENTS
page
ACKNOWLEDGMENTS iv
USTOFTABLES vii
LISTOFHOURES ix
KEYTOSYMBOLSORABBREVIATIONS xiv
ABSTRACT xvi
CHAPTERS
1 INTRODUCTION 1
2 SURFACTANTQUANTITATIVESTRUCTURE-PROPERTY
RELATIONSHIPS 4
Introduction 4
NonionicSurfactantCMC 6
AnionicSurfactantCMC 11
TemperatureDependenceofAnionicCMC 15
NonionicSurfactantCloudPoint 23
AnionicSurfactantKrafftPoint 28
MolecularVolumeofAlkanesandSurfactantHydrophobicTails 34
Conclusions 47
3 MAXIMUMSOLUBILIZATIONINNONIONICW/0MICROEMULSIONS....49
Introduction 49
NonionicSurfactants 50
Microemulsions 54
DesignofWater-in-OilMicroemulsions 62
Water/Hexadecane/SorbitanEsterMicroemulsions 69
EffectofOilPhaseonWater/Alkane/SorbitanEsterSystems 84
Water/Cyclohexane/NonylphenylEthoxylateMicroemulsions 95
OtherSolubilizationExperiments 101
Conclusions 105
V
4 SURFACTANTMICELLARLIFETIME 107
Introduction 108
AnionicSurfactants 109
InfluenceofAlcoholCosurfactantsonMicellarLifetime 110
InfluenceofGlycerolonMicellarLifetime 114
InfluenceofCounterionSizeonMicellarLifetime 122
InfluenceofAddedNonionicSurfactantonMicellarLifetime 131
InfluenceofAddedElectrolyteonMicellarLifetime 136
EffectofMolecularStructureonDynamicSurfaceTension 142
EffectofMicellarStructureon"NaNMRMeasurements 152
CationicSurfactants 160
MicellarLifetime 160
EffectofMicellarLifetimeonProcesses 169
NonionicSurfactants 175
SolvatochromisminNonionicSurfactants 176
DeterminationofAggregationNumberbyUVRayleighScattering 179
Conclusions 191
SUMMARYANDCONCLUSIONS 194
APPENDIX. SURFACTANTSUSEDINTHISRESEARCH 198
LISTOFREFERENCES 202
BIOGRAPHICALSKETCH 212
vi
LISTOFTABLES
Table page
2-1. CMCvalues(mM)for16structures,asafunctionoftemperature,and
Krafftpoints(°C) 18
2-2. Structurenamesforthe44surfactantsincludedintheKrafftpoint
correlations 31
2-3. Methodsforestimatingmolecularvolume 36
2-4. Structurenamesforthe78hydrocarbonsandfluorocarbonsusedforthe
determinationofmolecularvolume 40
3-1. Approveddailyintakevaluesforsomesurfactants 52
3-2. Specificrolesofcosurfactantinmicroemulsionformulation 59
3-3. TheeffectofoilsonthePITforvolumeratio1.0water/oilemulsion
containing10%POE(9.6)nonylphenylether 61
3-4. ExpectedstructuresfordifferentRvalues 63
3-5. Abe'smicroemulsiondesignrules 65
3-6. Surfactantmixturestudies 68
3-7. MaximumsolubilizationforSpansandTweens 81
3-8. Maximumsolubilizationindifferentoils 88
3-9. Mole fractions of Span and Tween 85 at the ratio of maximum
solubilizationindifferentalkaneoilphases 93
3-10. MaximumwatersolubilizationforIgepalCOmixturesinhexadecaneand
cyclohexane 98
3-11. Othersuccessfulmaximumsolubilizationexperiments 101
vii
3-12. Unsuccessfulmaximumsolubilizationexperiments 103
4-1. Solubilityofn-aliphaticalcoholsinwaterat25°C 112
4-2. Rulesforalcoholinfluenceonmicellarstability 114
4-3. Slowrelaxationtimeestimatesfor150mMSDS+salt(NaC104) 125
4-4. Slowrelaxationtime(X2)andelectricalconductivityforSDSmicellar
solutionswithdifferentconcentrationsofnonionicsurfactants 132
4-5. Slowrelaxationtime(T2)andelectricalconductivityforSDSmicellar
solutionswithdifferentconcentrationsofelectrolytes 138
4-6. Surfacetensionvalues(dyne/cm)at20°C 145
4-7. Surfacetensionandviscosityvalues(20°C,unlessotherwisemarked) 151
4-8. Absorbancepeaksandsolvatochromicshiftofselecteddyesinorganic
solvents 178
4-9. AbsorbancepeaksofSudanBlackBinselectedmicelles 179
4-10. Aggregationnumberofsometypicalnonionicsurfactantsasafunctionof
temperature 183
A-1. HLBandstructureofselectedsurfactants 198
viii
1
LISTOFHGURES
Figure page
2-1. StructuresofthesurfactantsincludedinthenonionicCMCcorrelations 8
2-2. Scatterplotforcalculatedvs.experimentalnonionicCMCfor77
surfactants,usingthreedescriptors 10
2-3. StructuresofthesurfactantsincludedintheanionicCMCcorrelations 13
2-4. Scatterplotforcalculatedvs.experimentalanionicCMCfor119
surfactants,usingthreedescriptors 14
2-5. NormalizedCMCvs.temperaturefora)sulfatesandb)sulfonates 21
2-6. Structuresofthesurfactantsincludedinthenonioniccloudpoint
correlations 25
2-7. Scatterplotforcalculatedvs.experimentalnonioniccloudpointfor62
surfactants,usingthreedescriptors 26
2-8. Topologicaldescriptorvaluesvs.carbonnumberforthedifferent
hydrophobicstructuresinthecloudpointcorrelation 27
2-9. StructuresofthesurfactantsincludedintheKrafftpointcorrelations 30
2-10. Scatterplotforcalculatedvs.experimentalKrafftpointfor44surfactants,
usingfourdescriptors 33
2-11. Scatterplotforthefourdescriptorregressionofcalculatedtoexperimental
molarvolumeof78diversealkanesandalkenes 42
2-12. Scatterplotfortheonedescriptor regressionofcalculatedto
experimentalmolarvolumeof78diversealkanesandalkenes,showing
structureswithgreateststericinfluenceonthemolecularvolume 44
3-1. W/0solubilization,binarymixturesofSpanswithTween85 73
ix
3-2. W/0solubilization,binarymixturesofSpanswithTween80 74
3-3. W/0solubilization,binarymixturesofSpanswithTween20 75
3-4. W/0solubilization,binarymixturesofSpanswithTween21 76
3-5. W/Osolubilization,binarymixturesofSpanswithTween81 78
3-6. Solubilizationassuminghydration,binarymixturesofSpanswithTween85 79
3-7. W/0solubilizationinternarySpan/Tweenmixtures 83
3-8. W/Osolubilization,weight%excursionforTween81 85
3-9. W/0solubilization,weight%excursionforSpan80/Tween85mixtures 86
3-10. W/Sratiovs.S/0ratio,forSpan80/Tween85Nhlb=10mixture 87
3-11. W/0solubilizationinCio-Cian-alkane/Tween81microemulsions 89
3-12. W/0solubilizationinCg-Cian-alkane/Span80/Tween85microemulsions 90
3-13. W/0solubilizationinCg-Cien-Alkane/Span20/Tween85microemulsions 91
3-14. W/OsolubilizationinCg,C12,C16n-alkane/Span20/Tween85
microemulsions 92
3-15. CurvaturemodelforthesolubilizationbehaviorofSpan/TweenW/0
microemulsions 94
3-16. W/0solubilization,binarymixtureswithIgepalCOseriessurfactantsin
cyclohexane 97
3-17. SolubilizationofelectrolytesolutionsinIgepal/cyclohexaneW/0
microemulsions 100
3-18. W/Osolubilizationinhexadecane/Span/ethoxylatedCastoroil
microemulsions 102
4-1. Effectofmicellarlifetime(slowrelaxationtime)ontechnologicalprocesses 108
4-2. Variationoftheslowrelaxationtime(T2)of100mMSDSasafunctionof
alcoholconcentration Ill
X