Spontaneous emulsification : mechanisms, physicochemical aspects and applications

170 Pages·2003·7.1 MB·English

by  Lopez-Montilla, Juan Carlos

SPONTANEOUSEMULSIFICATION:MECHANISMS,PHYSICOCHEMICAL
ASPECTSANDAPPLICATIONS
By
JUANCARLOSLOPEZ-MONTILLA
ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOL
OFTHEUNIVERSITYOFFLORIDAINPARTIALFULFILLMENT
OFTHEREQUIREMENTSFORTHEDEGREEOF
DOCTOROFPHILOSOPHY
UNIVERSITYOFFLORIDA
2003
Copyright2002
by
JuanCarlosLopez-Montilla
IModnetdiilclataedtehiLsopefefzo,rttotomtyhedpaeuogphlteerIJloohveantnhaeImsoasbte:lmLoypbeezlDouvreadnm,omthyergiBrelfrrtiheandEKdiuvviagne9s
TurkogluandmyfriendCarmendeLosRios,andtothememoryofmyfatherRafael
AlejandroLopezandofmygrandgrandmotherFranciscaLopez.
ACKNOWLEDGMENTS
TheauthorisgratefultotheEngineeringResearchCenterforParticleScienceand
Technology(ERC)oftheUniversityofFloridaforprovidingofcomputationaland
experimentalfacilities.Ialsothankfullyacknologethefinancialsupportrecivedbythe
UniversidaddelosAndes,FundacionGranMariscaldeAyacucho(Venezuela),the
UniversityofFlorida,andDr.DineshO.Shah.
IhavenotwordstothankDr.DineshO.Shahforwhathehasdoneforme.The
writtenandspokenlanguagesarenotappropriatelanguagestodescribethefeelingof
gratitudthatIhaveforhim.IcanjustsaythatIlovehim.IthankGodforallowingmeto
meetDr.Shah.
ToKivangTurkoglu,thelove,theunreachabledream,thewomanwhotookecare
ofmeduringthelastoneandahalfyearofmystudies.Iwillneverforgethergreat
dedicationtomeandthehappinessshegavetome.
ThereisagreatwomannamedCarmendeLosRios,withoutwhosehelpIwould
nothavebeenabletocomehere.Sheisthefriendeveryonedreamstohave,andsheis
justamazing.IthankCarmenforever.
I wouldalsoliketothankthefollowingpersons:Dr.OscarCrisalleforgivingme
theuniqueopportunityforjoiningtheUniversitytopursuemyPh.D.studies;Dr.Jean
LuisSalager,whohasbeenagreatsupportandinspirationsinceImethim;Dr.Conxita
Solans,abravewoman,forherinvaluablehelpinleadingmetounderstandthephase
behaviorofsurfactant-oil-watersystems.
IV
Iwouldliketothanktoallwhoinanunselfishfashionassistedmetofinishsome
oftheexperimentsandthemanuscripts.Namely,PauloHerrera,SamirPandey,Monica
James,andNathanLee.
Icansincerelysaythatwithoutthesupportofallthepeopleandinstitutions
mentioninthissection,itwouldhavebeenimpossibletoovercomethehugechallengeof
completingsuchafhiitful Ph.D.attheUniversityofFlorida.
IthankGodforhisinfinitekindnessduringmydifficultjourneyofthepastfew
years.
V
TABLEOFCONTENTS
ACKNOWLEDGMENTS iv
ABSTRACT x
CHAPTERS
1STATEOFTHEART 1
1.1Introduction 1
1.2MechanismsofSpontaneousEmulsification 5
1.2.1OriginalMechanisms 7
1.2.1.1Interfacialturbulence 7
1.2.1.2Diffusionandstranding 8
1.2.1.3Negativeinterfacialtension 10
1.2.2RecentlyProposedMechanisms 14
1.2.2.1Explosionofvesiclesbyosmoticgradient 15
1.2.2.2Inversionofahighlyviscousw/omicroemulsion
byosmoticgradient 17
1.2.2.3Sequentialchangesinstructures(bytemperaturegradient) 18
1.2.2.4Sequentialchangesinstructures(byconcentrationgradient) 19
1.2.2.5Myelinicfiguresandliquidcrystalexplosion 20
1.3PhaseBehaviorDiagrams 22
1.3.1DiffusionPathTheory 24
1.3.2SpontaneousEmulsificationDuetoTemperatureGradient 26
1.3.2.1Formationofhighlyconcentratedo/wemulsions
bydecreasingtemperature 28
1.3.2.2Formationofhighlyconcentratedw/oemulsionsbyincreasing
temperature 29
1.3.3SpontaneousEmulsificationDuetoConcentration
GradientofComponents 32
1.4TheoreticalApproachestoDescribeSomeAspectsof
SpontaneousEmulsification 34
1.5Applications 34
1.5.1Pesticides,InsecticidesandHerbicides 34
1.5.2Detergency 36
1.5.3Skin-careProducts 37
1.5.4DrugDeliverySystems:LipidFormulationsforOralAdministration 41
1.5.5FoodProducts:MayonnaiseandSaladDressings 44
1.5.6LubricantOilsforSpecificApplications:Cutting-fluids 47
VI
1.5.7EnhancedOilRecovery 49
1.61.5.8FormationofNano-emulsionsandNano-particles 51
1.5.9AsphaltEmulsions:BitumenEmulsion 52
SpontaneityofEmulsification 55
2MATERIALS,INSTRUMENTSANDMETHODS 58
2.1Materials 58
2.2Instruments 58
2.2.1Balance 58
2.2.2DropCounterSizer 58
2.2.3VideosandPhotographs 59
2.2.4Conductivity-TemperatureMeter 59
2.2.5pH-TemperatureMeter 59
2.2.6UV-visibleSpectrometer 59
2.3Systems 59
2.3.1SpontaneityoftheEmulsificationProcess 59
2.3.2LiquidCrystalInstability 60
2.3.3DiffusionandStranding,InterfacialTurbulence,
NegativeInterfacialTension,andRayleigh Instability 61
4 2.3.4Detergency 61
2.3.5WaterPurification 61
2.4Methods 63
2.4.1DeterminationofDropletSizeandIncrease
inInterfacialArea(SIAT)Method 63
2.4.2PhaseBehavior 64
2.4.3PhaseDiagram 64
2.4.4PhaseInversionTemperature(PIT) 65
2.4.5Spontaneity 65
2.4.6DiffusionandStranding,InterfacialTurbulence,
NegativeInterfacialTension,andRayleigh Instability 65
2.4.7DetergencyExperiments 66
2.4.8WaterPurification 66
3 ANEWMETHODTOQUANTITATIVELYDETERMINETHE
SPONTANEITYOFTHEEMULSIFICATIONPROCESS 68
3.1Introduction 68
3.2SpontaneityTests 69
3.2.1CPACTest 69
3.2.2TurbidityTest 70
3.2.3SpecificInterfacialAreaTest(SIAT) 71
3.3ResultsandDiscussion 72
3.4Conclusions 80
RANKINGOFFACTORSAFFECTINGSPONTANEOUSEMULSIFICATION....82
4.1Introduction 82
4.2ResultsandDiscussion 83
4.3Conclusions 91
5 AMOLECULARMECHANISMTOSPONTANEOUSLYPRODUCENANO-
EMULSIONSBYDESTABILIZINGLAMELLARLIQUID
CRYSTALLINEPHASE 93
5.1Introduction 93
5.2ResultsandDiscussion 95
5.3Conclusions 106
6 SPONTANEOUSEMULSIEICATIONMECHANISMSINRELATIONTO
EMULSIONDROPLETSIZE 108
6.1Introduction 108
6.2ResultsandDiscussion 109
6.3Conclusions 117
7THREEPROTOCOLSTOINDUCESPONTANEOUS
DETERGENCYTHUSINCREASINGBOTH
THEDETERGENCYEFFICIENCYANDEFFICACY 118
8.2
7.188..I22ntroduction 118
7.2ResultsandDiscussion 122
7.3Conclusions 126
8WATERPURIFICATION 128
9.1
8.1Introduction 128
8.2ExtractionofPollutants 129
Method1 129
Method2 129
PhaseDiagram:APowerfulToolforDesigningSeparationMethods 130
8.3ResultsandDiscussion 131
8.4Conclusions 139
9SUMMARYANDRECOMMENDATIONSFORFUTUREWORK 140
Summary 140
9.1.1ANewMethodtoQuantitativelyDeterminetheSpontaneityofthe
EmulsificationProcess 140
9.1.2SpontaneousEmulsificationMechanisms:LiquidCrystalInstability 141
9.1.3CorrelationbetweenSpontaneousEmulsificationMechanismsand
EmulsionDropSizeDistribution 141
9.1.4ApplycationsoftheSpontaneousEmulsificationPhenomenon:Detergency
andWaterTreatment 142
viii
9.2 9.1.4.1Detergency 143
9.1.4.2WaterPurification 143
RecommendationsforFuturework 144
SPONTANEOUSEMULSIFICATIONSYSTEMS 147
LISTOFREFERENCES 150
BIOGRAPHICALSKETCH 157
IX
AbstractofDissertationPresentedtotheGraduateSchool
oftheUniversityofFloridainPartialFulfillmentofthe
RequirementsfortheDegreeofDoctorofPhilosophy
SPONTANEOUSEMULSIFICATION:MECHANISMS,
PHYSICOCHEMICALASPECTSANDAPPLICATIONS
By
JuanCarlosLopez-Montilla
May2003
Chair:Dr.DineshO.Shah
MajorDepartment:ChemicalEngineering
Thisdissertationcomprisesmyresearchinspontaneousemulsificationtoproduce
thermodynamicallyunstablenano-emulsions. First,anewmethodtoquantitatively
determinethespontaneityoftheemulsificationprocesswasdesigned. Second,withthis
methodonhand,differentfactorsaffectingthedropsizedistributionandthemechanism
ofspontaneousemulsificationwereassessed(oil-chain-length,surfactantstructure,
surfactant-concentration,pH,salinity,synergismofsurfactantmixtures). Third,itwas
shownthatthepresence(orformationandposteriordestruction)ofliquidcrystalisan
essentialrequirementfortheformationofnano-emulsionwithlowenergyconsumption.
Fourth,acorrelationbetweenspontaneousemulsificationmechanismanddropsize
distributionwasestablished. Here,itwasshownthatinstabilitiesinducedtothe
structuresonself-assembledsystemssuchthatliquidcrystalandbicontinuous
microemulsionleadtotheformationofemulsionswithnano-sizedrops(<1pm). Onthe
X