Normal Case (Winsor) What is Solubilization? All phase diagrams contain a. in all cases

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1 / 72 UNICAMP Brazil, November 3, 2009 2 / 72 What is Solubilization?

Laboratory water monophasic zone polyphasic zone surfactant (+ alcohol) oil S+A height of polyphasic zone generally at center (Water/oil ratio = 1) 3 / 72 All phase diagrams contain a monophasic zone

1 1 / 72 UNICAMP Brazil, November 3, / 72 What is Solubilization? it is the ability of a surfactant to produce a monophasic system containing both oil and water Principles and Recent Advances with Extended Surfactant (smart) Structures Jean-Louis Salager FIRP Laboratory water monophasic zone polyphasic zone surfactant (+ alcohol) oil S+A height of polyphasic zone generally at center (Water/oil ratio = 1) 3 / 72 All phase diagrams contain a monophasic zone 4 / 72 The height of polyphasic zone at fixed oil/water composition (e.g. 50/50) is monitored Height S + A Formulation Scan If a formulation variable is changed (along a Formulation scan) How does solubilization change? Bourrel M., Schechter R. S., Microemulsions and Related Systems, Marcel Dekker, New York 1988 lowest height = maximum solubilization at optimum formulation Bourrel M., et al., The Topology of phase boundaries for oil-brinesurfactant systems and its relationship to oil Recovery, Society of Petroleum Engineers J., 22 (1), (1981) 5 / 72 Normal Case (Winsor) 6 / 72 in all cases S+A (%) Bourrel s gamma (γ) diagram 2! W I 1! 3! 2! W II sometimes called fish diagram the cross locates the point with highest solubilization Minimum S + A Formulation (e.g. (S) S) ptimum Formulation

7 / 72 Solubilization Parameters 8 / 72 At optimum formulation Bicontinuous

Solubilization parameter at crossing Formulation Scan Salager JL et al.

Chap 3, in Microemulsions, Background, New Concepts, Perspectives. C. Stubenrauch Ed.

- Wiley, xford (2009) 9 / 72 At optimum formulation Bicontinuous microemulsion

microemulsion zero curvature structure Scriven S.

Near R =1 curvature 0 Swollen Micelles large size 12 / 72 High solubilization

2 7 / 72 Solubilization Parameters 8 / 72 At optimum formulation Bicontinuous microemulsion SP water in m SP oil in m 3 φ Formulation Scan SP* Solubilization parameter at crossing Formulation Scan Salager JL et al. Formulation of microemulsions. Chap 3, in Microemulsions, Background, New Concepts, Perspectives. C. Stubenrauch Ed., Blackwell Pub. - Wiley, xford (2009) 9 / 72 At optimum formulation Bicontinuous microemulsion zero curvature structure 10 / 72 At optimum formulation Bicontinuous microemulsion zero curvature structure Scriven S., Nature 263: 123 (1976) 11 / 72 Transparent microemulsion? Near R =1 curvature 0 Swollen Micelles large size 12 / 72 High solubilization = 3φ with turbid microemulsions Surfactant Layer Solubilized Liquid Qty. of Surfactant depends on area α R 2 Solubilized Qty. depends on volume α R 3 SP α R 3 / R 2 valid for micelles and microemulsions SP* = ml/g γ* = mn/m

13 / 72 Tension-Solubilization Relationship Solubilization varies as the inverse of interfacial tension Reed R. L., Healy R. N., Some physicochemical aspects of microemulsion flooding: A review.

3 13 / 72 Tension-Solubilization Relationship Solubilization varies as the inverse of interfacial tension Reed R. L., Healy R. N., Some physicochemical aspects of microemulsion flooding: A review. In Improved il Recovery by Surfactant and Polymer Flooding, Shah D.. & Schechter R. S., Eds., Academic Press 1977 INTERFACIAL TENSIN (mn/m) ptimum Formulation Vo/Vs !! mo mw l m u 3 φ Salinity, % NaCl SP* Vw/Vs Formulation SLUBILIZATIN PARAMETERS ml/ml 14 / 72 Tension-Solubilization Relationship Solubilization varies as the inverse of interfacial tension γ x SP 2 = Constant The constant depends on surfactant (it is the same along the scan) Interfacial Tension mn/m C. Huh, J. Colloid Interface Sci. 71: (1979) variation tension-sp along a scan 0 20 Solubilization Parameters ml/g 15 / 72 Winsor s R Ratio of interactions 16 / 72 Winsor s R Ratio oil () surfactant (C) Aco Aco... R = = Acw... N D R = Aco - Aoo... = Acw - Aww... N D Maximum Solubilization when N = D but... water (W) Acw R = 1 = = = R < 1 R = 1 R > 1 is it the same thing? Winsor P. Solvent properties of amphiphilic compounds. Butterworths, London (1954) 17 / / 72 Winsor s Premise Examples R = 1 = = = higher interactions higher N (or D) higher solubilization BETTER Aco Acw Alkyl phenol ethoxylates / octane / no alcohol C8 Ø 5.3 E SP* = 5 ml/g C9 Ø 5.7 E SP* = 8 ml/g C12 Ø 8.3 E SP* = 20 ml/g N-hexane, 4.5 wt% NaCl, Surf/n-butanol=2/3 C12--S3Na C18-CH < CNa NHCCH3 SP* = 5.2 ml/g SP* = 15 ml/g

19 / 72 In order to change N or D formulation must be changed 20 / 72 Solubilization increases To keep R = 1 situation 2 variables

M., Chambu C., The Rules for Achieving High Solubilization of brine and oil by Amphiphilic Molecules.

, 23 : 327-338 (1983) But, when chain reaches 18 20 carbon atoms, the surfactant precipitates (Krafft Temperature) 21 / 72 Mixing

on both sides Avoids precipitation Increases packing Better interactions at interface Better packing High interfacial SP int * SP Vol

4 19 / 72 In order to change N or D formulation must be changed 20 / 72 Solubilization increases To keep R = 1 situation 2 variables (at least) must be changed Two alternatives 2 changes on different sides of interface 2 changes on the same side of interface Bourrel M., Chambu C., The Rules for Achieving High Solubilization of brine and oil by Amphiphilic Molecules. Society of Petroleum Engineers J., 23 : (1983) But, when chain reaches carbon atoms, the surfactant precipitates (Krafft Temperature) 21 / 72 Mixing lipophilic and hydrophilic species 22 / 72 Mixture of 2 different Surfactants increases interactions at interface Extends the reach on both sides Avoids precipitation Increases packing Better interactions at interface Better packing High interfacial SP int * SP Vol il or Water int * = Mass Adsorbed surfactant 23 / 72 Example 24 / 72 Beware that adding a short alcohol (balanced) cosurfactant decreases solubilization Increasing difference Reduces the average reach on both sides Decreases packing Graciaa A. et al. Langmuir 9, 1473 (1993)

$25 / 72 But unbalanced (segregated) additives increases solubilization Increases the average reach of surfactant Do not decreases packing LINKER concept 26 / 72 But mixtures fractionate Lipophilic$

5 25 / 72 But unbalanced (segregated) additives increases solubilization Increases the average reach of surfactant Do not decreases packing LINKER concept 26 / 72 But mixtures fractionate Lipophilic species go in oil Hydrophilic species in water = preferential partitioning nly a small % at interface = Surfactant loss = Low apparent SP app * SP app * = Vol il or Water Mass Total surfactant Graciaa A et al. Adv. Colloid Interface Sci , 63 (2006) Salager JL et al. Adv. Polymer Sci. 218: (2008) 27 / 72 Example = Lipophilic Linker + Surfactant 28 / 72 Caution There are (often) opposite phenomena, due to the complexity of the R expression Don t be afraid to go to the ER literature Increasing difference fractionation Bourrel M., Schechter R. S., Microemulsions and Related Systems, Marcel Dekker, New York 1988 Graciaa A., et al., Criteria for structuring to maximize solubilization of oil and water - I : Commercial non-ionics. Paper SPE/DE 9815, 2nd Joint SPE/DE Symposium on Enhanced il Recovery, Tulsa, April 5-8 (1981) Reed R. L., Healy R. N., Some physico-chemical aspects of microemulsion flooding: A review. in Improved oil recovery by surfactant and Polymer Flooding. Shah D., Schecheter R.S. Eds., pag 383 Academic Press (1977) Huh C., Interfacial tensions and solubilizing ability of a microemulsion phase that coexists with oil and Brine. J. Colloid Interface Science, 71 : (1979) Shiao S. Y., et al. The importance of sub-angstrom distaces in mixed surfactant systems for technological processes. Colloids Surfaces A, 128: 197 (1997) 29 / 72 In some cases Winsor s model does not explain the observed increase in solubilization 30 / 72 Proposed Mechanism The Lipophilic Linker increases interactions on the oil side by ordering the molecules deeper inside the oil bulk phase Lipophilic Additive increases solubilization Lipophilic Linker effect SP* ml/g M Surfactant Ethoxylated ctylphenol (EN near 5) Isooctane, WR =1, 25ºC Additive P 0 E P 1 E P 1.5 E P 3 E % aditivo en aceite % Additive in oil Graciaa A., et al. Improving Solubilization in Microemulsions with Additives - 1 : The lipophilic linker role, Langmuir 9 : (1993) ordered zone WATER IL ordered zone Interface INTERFACE IL WATER Lipophilic Linker

31 / 72 The Lipophilic Linker does not adsorb at interface (it is not a cosurfactant) is a slightly polar oil (or a very lipophilic amphiphile) is located inside oil phase near interface (interfacial

most polar substances in the oil phase which concentrate near interface The other phase and the surfactant only see the most superficial layer of the oil phase (similar to a chocolate covered candy)

6 31 / 72 The Lipophilic Linker does not adsorb at interface (it is not a cosurfactant) is a slightly polar oil (or a very lipophilic amphiphile) is located inside oil phase near interface (interfacial segregation) gets oriented perpendicular to interface stretches the reach of surfactant in oil (without producing precipitation) 32 / 72 The LIPPHILIC LINKER effect is due to the SEGREGATIN of the most polar substances in the oil phase which concentrate near interface The other phase and the surfactant only see the most superficial layer of the oil phase (similar to a chocolate covered candy) Interesting for applications! 33 / 72 Lipophilic Linker Role The L.L. stretches (in situ)... the surfactant hydrophobic tail The L.L. produces a slightly polar zone inside the oil phase, near the interface 34 / 72 Examples of Lipophilic Linkers Long chain n-alcohols ( > 8) Long chain alkylphenols ( > 8) idem slightly ethoxylated (EN < 2) Single chain esters (ethyl oleate) probably other linear lipophilic amphiphiles Graciaa A. et al., Improving Solubilization in Microemulsions with Additives - Part II : Long chain Alcohol as Lipophilic Linkers, Langmuir 9: 3371 (1993) Salager J.L, et al. Improving Solubilization in microemulsion with aditives - Part III: Lipophilic Linker ptimization J. Surfactants & Detergents 1: 403 (1998) 35 / 72 Alcohol (LL) Mixture 36 / 72 Alcohols as Lipophilic Linkers Mixing LL improves solubilization = Longer LL SP (ml/g) DDECYL EN* NNYL CTYL ALCHL CARBN NUMBER 0.02 M Ethoxylated Alkylphenol T = 25 C M n-alcohol Isooctane WR = 1 Lipophilic Linker effect adds up to surfactant effect

37 / 72 The Lipophilic Linker is...... a very lipophilic amphiphile or a polar oil...... which acts at very low concentration because it locates itself...... near interface It is not a case of adsorption.

7 37 / 72 The Lipophilic Linker is a very lipophilic amphiphile or a polar oil which acts at very low concentration because it locates itself near interface It is not a case of adsorption but of segregation 38 / 72 Interfacial Segregation Take a oil mixture (same molar volume oils) Hexadecane > non polar (ACN=16) Ethyl leate > polar (EACN=6) Measure or evaluate interfacial tension optimum formulation oil composition near interface Graciaa A. et al., Interfacial Segregation of Ethyl leate/hexadecane il Mixture in Microemulsion Systems, Langmuir 9: 1473 (1993) 39 / 72 0 interfacial Tension Interfacial Segregation il ETHYL LEATE { HEXADECANE ETHYL LEATE FRACTIN in IL 1 Everything happens as if the interfacial oil were pure polar oil, when there is 50% of this oil in the mixture (green arrow) = polar oil segregation near interface 40 / 72 Naphtalene Sulfonate = hydrotrope H 3 C H 3 C H 3 C Hydrophilic Linker S 3 Na S 3 Na S 3 Na Di-butyl Naphtalene Sulfonate = hydrophilic surfactant H 3 C-CH 2 -CH 2 -CH 2 H 3 C-CH 2 -CH 2 -CH 2 S 3 Na Mono/Dimethyl Naphtalene Sulfonate = hydrophilic linker 41 / 72 di-hexyl-sulfosuccinate Hydrophilic Linker Similar role on the water side althought much less The H.L. produces a slightly less polar zone in the water phase, close to interface Acosta E. et al, The Role of Hydrophilic Linkers, J. Surfactants Detergents, 5: 151 (2002) 42 / 72 Lipophilic and Hydrophilic Linkers = thickness + mixture But fractionation oil Lipohilic Linker adsorbed Surfactant Hydrophilic Linker water produce: Better match (oil does not contact water) Continuous polarity variation Graciaa A. Langmuir 9, 1473 & 9, 3371 (1993) Salager JL J. Surf. Deterg 1, 403 (1998) Uchiyama H. Ind. Eng. Chem. Res 39, 2704 (2000) Acosta E. J. Surf. Deterg 5, 151 (2002)

8 43 / 72 Amphiphilic Linker = thickness + mixture + no fractionation But precipitates It becomes anchored on both sides of interface (low MW diblock polymer) LL effect 44 / 72 There is no precipitation problem only if used at very low concentration Considerable enhancement of solubilization Jakobs B. et al., Langmuir 15, 6707 (1999) anchored at interface HL effect Favorables factors are : continuity in interfacial transition and a good match on both sides no partitioning 45 / 72 Intra -molecular mixture (= no partitioning) What should be done? Far away reach Longer is K but must avoid Thick intermediate zone precipitation but no precipitation problem (mixture + intermediate polarity)} Good hydrophilic interaction } Interface here! Easier to get a good interaction with water 46 / 72 Surfactant+linker effect could be attained with a single extended surfactant! = intramolecular mixture Surfactant? hydrophobic chain hydrophilic group + Linker Extended Surfactant Spacer arm is hydrophobic but slightly polar PLY- PRPYLENE XIDE 47 / 72 Extended Surfactants (1 rst Generation) dodecyl poly-propylene oxide (variable length) = mixture feature 48 / 72 depend on Propylene xide Number (PN) When PN increases CMC decreases Cloud Point is lowered ptimum Salinity (3φ) decreases ethoxy (2E) sulfate sodium salt Miñana M. et al., Solubilization of Polar oils in Microemulsion Systems, Progress Colloid Polymer Science, 98 : (1995) Conclusion: When PN increases surfactant becomes more lipophilic... but does not precipitate (mixture)

49 / 72 50 / 72 Usual behavior of anionics Ln S = k ACN +.

% extended Surfactants Ethyl leate Hexadecane Mygyol 812 Soja oil 0 6 10 14 PRPYLENE XIDE NUMBER Miñana-Perez M. et al., Solubilization of Polar ils with Extended Surfactants, Colloids Surfaces A.

51 / 72 ES produce 3 φ with HIGH SLUBILIZATIN and LW TENSIN with polar oils 52 / 72 Micellar aggregation of extended surfactant Intermediate polarity zone Lipophilic Core Ethyl oleate Miglyols Soya

9 49 / / 72 Usual behavior of anionics Ln S = k ACN +... Idem but k depends on PN ES Produce a high SLUBILIZATIN and LW TENSIN particularly with natural oils Soja oil = natural triglyceride SP (ml/g) WR = 1 T = 35 C 1.25 wt.% extended Surfactants Ethyl leate Hexadecane Mygyol 812 Soja oil PRPYLENE XIDE NUMBER Miñana-Perez M. et al., Solubilization of Polar ils with Extended Surfactants, Colloids Surfaces A. 100 : (1995). 51 / 72 ES produce 3 φ with HIGH SLUBILIZATIN and LW TENSIN with polar oils 52 / 72 Micellar aggregation of extended surfactant Intermediate polarity zone Lipophilic Core Ethyl oleate Miglyols Soya il Miñana-Pérez M. et al., Solubilization of Polar ils with Extended Surfactants, Colloids Surfaces A. 100 : (1995). PolyP spacer S4 Group Fernández A., MSc Thesis, Universidad de Los Andes (2002) S4 Group Hydrophilic Groups 53 / 72 Micellar aggregation of extended surfactant 54 / 72 Intermediate polarity zone Usually SP* decreases as ACN increases At low PN it does too! At high PN it increases with ACN Good for LNG ALKANES At PN=10 SP* does not vary with ACN SP* increases with alkyl tail Large volume in which polar oil can be solubilized Salager J.L et al., 7th Word Surfactant Congress CESI, Paris, June 2008

55 / 72 56 / 72 Usual mixing rule vs formulation Mixing rule of ES with nonionics As far as SP* MIX is concerned the rule is (only) approximately linear for polar oils and dependent only on extended

57 / 72 ES with PP less hydrophilic as Temp increases First 2 3 Ps are wet by water! ANINICS PolyE NNINICS ES with PP Independent of PN Velasquez J. et al., Effect of the temperature J.

.. poor Some samples of alkyl PolyP (E) sulfates have been prepared by three surfactant manufacturers (Seppic, Sasol, Hunstman) and some studies reported. 60 / 72 Recent Publications GETHALS G. et al.

10 55 / / 72 Usual mixing rule vs formulation Mixing rule of ES with nonionics As far as SP* MIX is concerned the rule is (only) approximately linear for polar oils and dependent only on extended surfactant ther surfactants ] beys HLD = β kacn + b S f(a) + c T (T-25) With β = α EN for C9EN Mixture feature does not work the same way! 57 / 72 ES with PP less hydrophilic as Temp increases First 2 3 Ps are wet by water! ANINICS PolyE NNINICS ES with PP Independent of PN Velasquez J. et al., Effect of the temperature J. Surfactants Deterg. published on line (2009) 58 / 72 ES with PP less hydrophilic as Temp increases ther Ps are not! First 2 3 P groups are wet by water! 59 / 72 Current availability... poor Some samples of alkyl PolyP (E) sulfates have been prepared by three surfactant manufacturers (Seppic, Sasol, Hunstman) and some studies reported. 60 / 72 Recent Publications GETHALS G. et al., Spacer Arm influence on Glucido-amphiphilic Compound Properties, Carbohydrate Polymers 45 : 147 (2001) SCRZA C. et al., Synthèse de dérivés polypropilèneglycol à tête glucidyl ou ityl comme surfactifs, XVIIº Journées Chimie et Chimie des Glucides, Tregastel, France, June 1998 SCRZA C., et al., New amphiphilic polypropileneglycol derivatives with carbohydrate polar head, 24º Congr. Anual Comite Español Detergencia, Barcelona, Spain, May 1999 SCRZZA C., et al., Synthesis and Surfactant Properties of a new "extended" glucidoamphiphile made from D-Glucose, J. Surfactants & Detergents,, 5: 331 (2002) SCRZZA C., et al., An other new familly of "extended" Glucidoamphiphiles. Synthesis and Surfactant Properties for different Sugar head Groups and Spacer Arm lengths, J. Surfactants & Detergents,, 5: 337 (2002) HUANG L. et al. Microemulsification of triglyceride sebum and the role of interfacial structure on bicontinuous phase behavior. Langmuir 2004, 20: (2004) FERNANDEZ A. et al., Synthesis of new extended surfactants containing a carboxylate or sulfate polar group. J. Surfactants Detergents 8: 187 (2005) FERNANDEZ A., et al., Synthesis of new extended surfactants containing a Xylitol polar group. J. Surfactants Detergents 8: 193 (2005) WITTHAYAPANYANN A., et al. Formulation of ultralow interfacial tension systems using extended surfactants, J. Surfactants Detergents 9: 331 (2006) SALAGER J. L. et al. Amphiphilic mixture versus surfactant structure with smooth polarity transition across interface to improve solubilization performance. CESI th World Surfactant Congress Paris, June Proceedings Paper -A17. WITTHAYAPANYANN A., et al. HLD method for characterizing coventional and extended surfactants. J. Colloid Interface Sci. 325: 259 (2008)

11 61 / / 72 2 nd Generation of extended surfactants for biocompatible applications ptimize nature and size of the 3 pieces: Adjust structure to oil nature New generation of extended surfactants: Biocompatible green polar groups Determine mixing rules Conventional + extended surfactants sugar polar group taylored spacer arm Fatty acid derivative (hydrophobic tail) Physico-chemical Properties of theses Products are under study Goethals G. et al., Spacer Arm influence on Glucido-amphiphilic Compound Properties, Carbohydrate Polymers, 45 : (2001) 63 / 72 Polar heads (simple or combined) currently synthesized and tested Linear C12-C18 chain attached at end or center saturated or unsaturated Different kinds of spacers you could think about Different head groups sulfate ethoxy-sulfate carboxylate ethoxy-carboxylate C6 sugars xylitol (C5 sugar) di-xylitol ethoxy-xylitol carboxylate & xylitol carboxylate & glucose 64 / 72 C 12 H 25 n extended soaps _ + C 2 Na Fernandez A. et al., Synthesis of new extended surfactants containing a carboxylate or sulfate polar group. J. Surfactants Detergents 8: 187 (2005) 65 / 72 extended alkyl monoglycoside 66 / 72 C 12 H 25 n z Z = Xylitol H H R n H H H Scorzza C. et al., J. Surfactants & Detergents, 5 (4) & (2002) H extended monodi-xylitol a non-cyclic glycoside C 12 H 25 n z z _ + Na H Fernandez et al., Synthesis of new extended surfactants containing a Xylitol polar group J. Surfactants Detergents 8: : 193 (2005) H H H H H

67 / 72 68 / 72 Potencial Applications Current best solubilization : 1 g of high performance extended surfactant can solubilize almost 40 g of hexadecane or ethyl oleate and 15 g of C18 triglyceride

surf. combine with asphaltenes) For some applications, the used surfactants must be completely biocompatible, biodegradable, non-toxic, green etc!

12 67 / / 72 Potencial Applications Current best solubilization : 1 g of high performance extended surfactant can solubilize almost 40 g of hexadecane or ethyl oleate and 15 g of C18 triglyceride Microemulsions to be directly injected in blood stream (Drugs are generally oil soluble) Soak-only Detergents (no stirring required) Solvent like extraction (e.g. edible oil in pressing residue) Transdermic transfer (pharmaceuticals and cosmetics) Crude il dehydration (ext. surf. combine with asphaltenes) For some applications, the used surfactants must be completely biocompatible, biodegradable, non-toxic, green etc! 69 / 72 Just a slight improvement in solubilization and the original R&D goal (1987) may be attained Infinite (microemulsion) dilution in blood of a biocompatible oil containing a lipophilic drug ( ) 70 / 72 Solubilization may be increased by increasing the thickness of the polar-apolar transition zone: Increasing the surfactant size... up to a limit > precipitation Using a mixture of Lipo-/Hydro-philic amphiphiles... up to a limit > partitioning Using an intramolecular mixture with spacer arm of intermediate polarity = extented surfactant... Probably better if intermediate is a mixture (polyp)... up to a limit... to be found! 71 / 72 A Comment on this Research Progress PRGRESS LIPPHILIC LINKER Property Understanding according to Winsor anomaly diagnostic interpretation EXTENDED SURFACTANT innovation Understanding properties New structures, Biocompatibility issues TIME / 72 Visit us at More information: Salager JL et al., Enhancing Solubilization in Microemulsion State of the Art and Current Trends, J. Surfactants Detergents 8 : 3-21 (2005)

W III. Formulation Scan! W II W I. What is Solubilization?! All phase diagrams contain a. Phase behavior!

W III. Formulation Scan! W II W I. What is Solubilization?! All phase diagrams contain a. Phase behavior! 1 / 235 44 th American Chemical Society National Meeting, New rleans LA USA, April 6-10, 2008 2 / 44 What is Solubilization? it is the ability of a surfactant to produce a monophasic system containing