Trends in Colloid and Interface Science V

511 Pages·1991·9.13 MB·English

by  S. A. Safran, F. C. MacKintosh, P. A. Pincus (auth.), F. Mallamace (eds.)

Progress in Colloid & Polymer Science • Vol. 84
PROGRESS IN COLLOID & POLYMER SCIENCE
Editors: H.-G. Kilian (Ulm) and G. Lagaly (Kiel)
Volume 84 (1991)
Trends in Colloid
and Interface Science V
Guest Editor: M. Corti (Pavia)
and F. Mallamace (Messina)
Steinkopff Verlag • Darmstadt
Springer-Verlag • N e w York
0 4
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Preface
The first meeting of the European Colloid and In- mittee: M. Almgren, S. J. Candau, R. Klein, R. H.
terface Society (ECIS) was held in Como, Italy, in Ottewfll, R. Strey and M. Zulauf; from the Italian
1987. Three years later, following meetings in Ar- Ministry of University and Scientific Research, Prof.
cachon and Basel, the ECIS Conference was again A. Ruberti, and the President of the Regional
held in Italy at Copanello di Catanzaro in Government of Calabria, Dr. R. Olivo, both for their
September 1990. This gathering was attended by dedicated patronage; from the city of Catanzaro,
participants from 21 countries, including the USA Mayor Dr. M. Furriolo and Cultural Attach6 G.
and Russia. More than 150 papers were presented Guerriero; Prof. G. Stagno D~lcontres, Rector of
either orally or as posters. This volume includes Messina University; and the generous sponsors
most of these papers, which have been rather ar- who made the Copanello meeting possible: The
bitrarily subdivided into six sections: Micelles, Italian Consiglio Nazionale delle Ricerche support-
Microemulsions, Application of Colloids, Interac- ing the publication of this issue, the Departiment of
tion and Ordering, Biological Macromolecules, and Physics of Messina University, the Assessorato
Layers and Interfaces. The interdisciplinary nature Agricoltura della Regione Calabria, IBM-Italy, Spec-
of these fields bordering between physics and tra Physics, dB Electronics, and Chemifarm. Finally,
chemistry is evident. Unfortunately, it was, of particular thanks go to our hosts and the staff of
course impossible to reproduce in this volume the Villaggio Guglielmo in Copanello for their
lively, friendly atmosphere of the meeting; discus- hospitality.
sions outside the conference room were wide-rang-
ing and fruitful.
On behalf of the ECIS, we thank: all the par- Mario Corti
ticipants for their contributions; the scientific co r n - Franco Mallamace
Contents VII
Contents
Preface V
Micelles
Safran SA, MacKintosh FC, Pincus PA, Andelman DA: Spontaneous vesicle formation by mixed surfactants. 3
Thalberg K, Lindman B, Karlstr6m G: Electrolyte dependent phase separation in aqueous mixtures of a polyelec-
trolyte and an ionic surfactant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
van Stare J, Almgren M, Lindblad C: Sodium dodecylsulfate-poly(ethyleneoxide) interactions studied by time-
resolved fluorescence quenching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Cantu L, Corti M, Musolino M, Salina P: Spontaneous vesicle formation from a one-component solution of a
biological surfactant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Hoffmannn H, Hofmann S, Rauscher A, Kalus J: Shear-induced transitions in micellar solutions . . . . . . . . . . . 24
Lin T-L, Liu C-C, Roberts ME Chen S-H: Mixed short-chain lecithin/long-chain lecithin aggregates studied by
small-angle neutron scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Appell J, Porte G: Polymer-like giant micelles. An investigation by light scattering . . . . . . . . . . . . . . . . . . . . . . . . 41
Glatter O: Scattering studies on colloids of biological interest (Amphiphilic systems) . . . . . . . . . . . . . . . . . . . . . . 46
Baglioni P, Dei L, Ferroni E, Kevan L: Electron spin echo modulation and electron spin resonance studies of
sodium dodecylsulfate and dodecyltrimethylammonium bromide micellar solutons: Effect of urea addition 55
Hill A, Candau F, Selb J: Aqueous solution properties of hydrophobically associating copolymers . . . . . . . . . . 61
Despotovi4 R: On mixed surfactant systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Miinch C, Hoffmann H, Ibel K, Kalus J, Neubauer G, Schmelzer U, Selbach J: A shear-induced structure transi-
tion on a micellar solution measured by time-dependent small-angle neutron scattering . . . . . . . . . . . . . . . . . 69
J6hnannsson R, Almgren M: A fluorescence and phosphorescence study of AOT/H20/aikane systems in the L 2
reversed micellar phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
L6froth J-E, Johansson L, Norman A-C, Wettstr6m K: Interactions between surfactants and polymers. I: HPMC 73
L6froth J-E, Johansson L, Norman A-C, Wettstr6m K: Interactions between surfactants and polymers. Ih
Polyelectrolytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Malliaris A, Binana-Limbele W: Solubilization of aprotic additives in aqueous micelles . . . . . . . . . . . . . . . . . . . . 83
Tsiourvas D, Paleos CM, Malliaris A: Aggregation of polyamphiphiles with the polar head on the main chain 86
Onori G, Ronca M, Santucci A: Properties of water solubilized in reversed AOT micelles from near-infrared
spectra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Onori G, Ronca M, Santucci A: Shape and solvation of water-containing reversed AOT micelles from viscosity
measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Ravey JC, Gherbi A, St6b6 MJ: Mixed systems of fluorinated and hydrogenated nonionic surfactants: The
air/water adsorbed film and micelles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Rauscher A, Rehage H, Hoffmann H: Stretched exponential relaxation processes in viscoelastic surfactant
solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Schubert K-V, Strey R, Kahlweit M: 3PHEX: A new surfactant purification technique . . . . . . . . . . . . . . . . . . . . . . 103
Tondre C, Derouiche A: Solubilization of electrolyte solutions in AOT reversed micelles. Conductivity percola-
tion and phase behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Treiner C, Bury R: Peculiar micellar solubilization of benzyl alcohol in binary benzyldimethyltetradecylam-
monium chloride and trimethyltetradecylammonium chloride solutions: A calorimetric investigation . . . . . . 108
Korolenko EC, Shokhirev NV: Spin-controlled reactions on the micellar surface . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
Microemulsions
Teixeira J, Alba-Simionesco C, Angell CA: Glass transition in microemulsions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Senatra D, Lendinara L, Giri MG: W/O microemulsions as model systems for the study of water confined in
microenvironments: Low resolution 1H magnetic resonance relaxation analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 122
VIII Progress in Colloid & Polymer Science, Vol. 84 (1991)
Atkinson PJ, Clark DC, Howe AM, Heenan RK, Robinson BH: Characterization of microemulsion-based organo-
gels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
Baglioni P, Gambi CMC, Goldfarb D: Pulse electron spin resonance and quasi-elastic light scattering of Winsor
microemulsions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Rouch J, Safouane L, Cametti C, Codastefano P, Tartaglia P, Chen SH: A dynamic transition at the percolation
threshold of a three-component microemulsion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Paillette M: Phase electric birefringence measurements in attractive-type W/O microemulsion systems . . . . . . . 144
Liano P, Duportail G: Fractal models for luminescence probing of organized assemblies. Studies with respect
to the nature of the assembly, the temperature, and the quencher concentration . . . . . . . . . . . . . . . . . . . . . . . . 151
Mallamace F, Magazu S, Micali N, Salvetti P: Microemulsion as model system for the study of the glass-like tran-
sition: Refractive index and calorimetric measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Mallamace F, Micali N, Vasi C, D?~rragio G, Paparelli A: Hypersound velocity measurements in dense
microemulsions, evidence of a viscoelastic behavior connected with the percolation process . . . . . . . . . . . . . . 159
Interfaces
Woermann D: Critical phenomena in associative binary liquid mixtures with miscibility gap . . . . . . . . . . . . . . . 165
Kuzmin SV, Malomuzh NP: Surface-induced polarization properties of highly viscous liquids . . . . . . . . . . . . . . 171
Dgkrrigo G, MaUamace E Micali N, Paparelli A, Teixeira J, Vasi C: Aggregation phenomena in water-alcohol solu-
tions. Thermodynamic and dynamic studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
Aveyard R, Binks BP, Fletcher PDI: Effects of subphase pH on the successive deposition of monolayers of
docosanoic acid onto mica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
Gambaro M, Gliozzi A, Robello M: Effect of surface charges on the electroporation process in lipid bilayers. 189
Meunier J, Henon S: Optical study of monolayers at liquid interfaces: Direct observation of first order phase tran-
sitions and measurement of the bending elastic constant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
Nahrinbauer h The interaction between polymer and surfactant as revealed by interfacial tension . . . . . . . . . . 200
R6hl W, von Rybinski W, Schwuger MJ: Adsorption of surfactants on low-charged layer silicates. Part I: Adsorp-
tion of cationic surfactants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
Bartolotta A, Di Marco G, Carini G, Tripodo G: Study of local and cooperative molecular movements in Po-
ly(ethylene oxide) -- Potassium thiocyanate complexes by mechanical measurements . . . . . . . . . . . . . . . . . . . . 215
Caminati G, Tomalia DA, Turro NJ: Photo-induced electron transfer at polyelectrolyte-water interface . . . . . . . 219
da Gra~a M. Miguel M, Burrows HD: Luminescence study of fluidity in the La mesophase and liquid phase of
lead(H) decanoate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
Bartolotta A, Di Marco G, Carini G, Tripodo G: Relaxation processes in polymeric electrolytes: Effect of the ca-
tion size and of the thermal history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
Gabrielli G, Puggelli M, Prelazzi G: Mono- and multi-layers containing ion carriers . . . . . . . . . . . . . . . . . . . . . . . 232
Gallegos C, Nieto M, Nieto C, Mufioz J: Influence of surfactant concentration on the time-dependent theological
behavior of the lamellar liquid crystal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
G6bel S, Hiltrop K: Influence of organic counterions on the structure of lyotropic mesophases . . . . . . . . . . . . . 241
Miller CA, Gradzielski M, Hoffmann H, Kr/imer U, Thunig C: L3 phases: Their structure and dynamic
properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
Kaeder U, Hiltrop K: Alignment of lyotropic nematics by surface action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
Lachaise J, Sahnoun S, Dicharry C, Mendiboure B, Salager JL: Improved determination of the initial structure
of liquid foams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
Papirer E, Perrin JM, Siffert B, Philipponneau G: Surface characteristics of colloidal aluminas and barium
titanates determined by inverse gas chromatography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
Sch6n G, Peschel G, Stobbe H: Impedance-spectroscopic investigations of water structure near silica surfaces 262
Porte G, Appell J, Bassereau P, Marignan M, Skouri M, Billard I, Delsanti M, Candau SJ, Strey R, Jahn W, Snabre
P: Scaling laws for some physical properties of the L3 phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
Paluch M: Effect of halogeno substituted ethyl alcohols on the surface potential and on the surface tension at
the water/air interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
Burger A, Rehage H: Two-dimensional model networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
Rolandi R, Dante S, Maga L, Robello M: Domains formation in polymerized monolayers revealed by
fluorescence microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
Schroder A, Candau SJ: Study of the swelling of latex particles by means of ultrasonic techniques . . . . . . . . . 275
Vandevyver M, Roulliay M, Bourgoin JP, Barraud A, Morand JP, Noel O: Structure-reactivity relationship in
Langmuir-Blodgett films of bisethylenedithio-tetrathiafulvalene (BEDT-TFF) derivatives . . . . . . . . . . . . . . . . . . . 279
Has M, Lfidemann H-D: p,T dependence of the hydrophobic interaction in a model solution . . . . . . . . . . . . . . 283
Shokhirev NV, Burshtein AI: The change in density and pressure tensor at the liquid-vapor interface . . . . . . . 285
Contents IX
Vituhknovsky AG, Sluch MI: Optical properties of Langmuir-Blodgett films: perylene excimer formation . . . . 288
Churaev N, Kotov A, Solometsev Y, Starov V: The influence of charged gel layers on the electrokinetic
phenomena . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
Kotov A, Solomentsev Y, Starov V: Direct approach of two particles covered with a porous layer . . . . . . . . . . . 293
Application of Colloids
Bongiovanni R, Ottewill RH, Rennie AR: Small-angle neutron scattering from dispersions of organophilic clays 299
Carpineti M, Giglio M, Paginini E, Perini U: Low-angle static light scattering by fast aggregation of polystyrene
latex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
Siffert B, Badri F: Competition between micellization and adsorption of alkyl-PEO diblock copolymers on
titanium dioxide particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309
Fucile E, Denti P, Saija R, Borghese F, Sindoni OI: Density dependence of the extinction coefficient of a disper-
sion of spherical metal particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
Carri6n Fit6 FJ: Electrokinetic behavior of polyester and solid impurity during washing process in the presence
of cellulose ethers and NTA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319
Herzog B: Micelle shape and capacity of solubilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Callejas-Fern~indez J, de las Nieves FJ, Martinez-Garcfa R, Hidalgo-Alvarez R: Electrokinetic characterization and
colloid stability of calcium oxalate monohydrate dispersions in the presence of certain inhibitors . . . . . . . . . . 327
Jenta TR-J, Robinson BH, Batts G, Thomson AR: Enzyme kinetic studies using lipase immobilised in microemul-
sion-based organogels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334
Mendiboure B, Graciaa A, Lachaise J, Marion G, Bourrel M, Salager JL: Influence of the intensity of mixing on
the droplet size distribution of emulsions: Theory and experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338
Lisiecki I, Lixon P, Pileni MP: Synthesis in situ in reverse micelle of copper metallic clusters . . . . . . . . . . . . . . . 342
Tondre C, Claude-Montigny B, Ismael M, Scrimin P, Tecilla P: Metal-ion complexation by micelle-solubilized
long-chain complexing agents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345
Te~ak D, Heimer S, Derek V, Strajnar F: Precipitation of aluminium with surfactant in sea-water . . . . . . . . . . . 348
Palberg T, Hartl W, Deggelmann M, Simnacher E, Weber R: Comparison of charge numbers of interacting latex
spheres from different experiments: Conductivity, electrophoresis, torsional resonance detection, and static
light scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352
Schulz SF, Maier EE, Hagenbfichle M, Graf Ch, Weber R: Structural properties of dilute aqueous solutions of
charged rods studied by light-scattering techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356
Di Biasio A, Bolle G, Cametti C, Codastefano P, Tartaglia P: Light scattering from aggregating colloids: Stretched
exponential behavior of the time correlation function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359
Weyerich B, DAguanno B, Canessa E, Klein R: On the structure of suspensions of charged rodlike particles. 362
Interaction and Ordering
Candau SJ, Ilmain F, Moussa'id A, Schosseler F: Structure and properties of partially neutralized poly(acrylic
acid) gels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369
Ostrowsky N, Gamier N: Brownian dynamics close to a wall, measured by quasi-elastic light scattering from
an evanescent wave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371
Arauz JL, Ruiz-Estrada H, Medina-Noyola M, Nagele G, Klein R: Tracer-diffusion in binary mixtures of charged
spherical macroparticles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377
D~guanno B, M6ndez-Alcaraz J, Klein R: Structure and thermodynamics of mixtures of charged spherical col-
loidal particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381
Granfeldt MK, J6nsson B, Woodward CE: The interaction between charged colloids with adsorbed
polyelectrolytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391
Palberg T, Simon R, Leiderer P: Forced Rayleigh scattering in mixtures of colloidal particles . . . . . . . . . . . . . . . . 397
Mimouni Z, Mathis C, Bossis G: Analysis of alignments of colloidal spheres by light scattering . . . . . . . . . . . . 402
Peschel G, van Brevern O: The contribution of hydration forces to particle-particle interaction in a silica hydrosol 405
Chang S-L, Chen S-H, Rill RL, Lin JS: Measurement and interpretation of counterion distribution around cyclin-
drical polyelectrolytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409
Chabalgoity-Rodrfguez A, Marffn-Rodrfguez A, Galisteo-Gonz~lez F, Hidalgo-Alvarez R: Electrophoretic mobili-
ty, primary electroviscous effect and colloid stability of highly charged polystyrene latexes . . . . . . . . . . . . . . . 416
Lemaire E, Paparoditis C, Bossis G: Yield stress in magnetic suspensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425
Mallamace F, Micali N, Vasi C: Role of the ionic strength in the viscosity of charged colloids . . . . . . . . . . . . . . . 428
X Con~n~
Bio log ica l Macrom o l e s
Margheri E, Bonosi F, GabrieUi G, Martini G: Spectroscopic investigation on the effect of the addition of
ceramide into lipid vesicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
Giordono R, Grasso A, Teixeira J, Wanderlingh E Wanderlingh U: SANS in lysozyme solutions . . . . . . . . . . . . 439
Huruguen JP, Pileni MP: Changes in the percolation threshold by cytochrome c addition in AOT reverse micelles 442
Gallardo V, Bolivar M, Salcedo J, Delgado AV: A study of the effect of different amino acids on the electrical
properties of nitrofurantoin suspensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447
De Cuyper M, Joniau M: Effect of dimethylsulfoxide on the kinetics and thermodynamics of asymmetric
phospholipid fluxes between magnetic and non-magnetic vesicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 456
Deriu A, Cavatorta E Cabrini D, Middendorf HD: Molecular structure and dynamics of biopoylmer gels by
neutron scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 461
Cametti C, De Luca E D'nario A, Macri MA, Briganti G, Maraviglia B: The ripple phase in model membrane
systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465
Domazou AS, Mantaka-Marketou AE: Fluidity variation of DODAB vesicular membranes with estrogen hor-
mone using the lucigenin chemiluminescent reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 470
Edwards K, Almgren M: Solubilization of lecithin vesicles by C12E8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 472
Fisicaro E, Pelizzetti E, Lanfredi E, Savarino P: Osmotic coefficients of N-nonyl- and N-decyl-nicotinamide
chloride surfactant aqueous solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474
Aliotta E Fontanella ME, Magazu" S, Wandeflingth F: Hypersonic properties in macromolecular aqueous
solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
Giordano R, Grasso A, Wanderlingh F, Wanderlingh U: Static and dynamic properties in thixotropic structures 487
G~ilvez-Ruiz MJ, Cabrerizo-Vflchez MA, Galisteo-Gonz~lez F, Hidalgo-Alvarez R: Study of temperature and pH
effects on phase transition liquid expanded/liquid condensed of cholesterol, lecithin and lithocholic acid mixed
monolayers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494
Seras M, GrabieUe-Madelmont C, Paternostre M-T, Ollivon M, Handjani-Vila R-M: Study of non-ionic
monoalkyl amphiphile-cholesterol vesicles solubilization by octylglucoside . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
Staunton S, Quiquampoix H: The use of a trace amount of methylated bovine serum albumin as a probe of the
state of bovine serum albumin adsorbed on montmorillonite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506
Xenakis A, Valis TP, Kolisis N" Microemulsions as a tool for enzymatic studies: The case of lipase . . . . . . . . . . 508
Author Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 512
Subject Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514
Progress in Colloid & Polymer Science Progr Colloid Polym Sci 84:3--7 (1991)
Spontaneous vesicle formation by mixed surfactants
S. A. Safranl'4), E C. MacKintosh1), P. A. Pincus2), and D. A. Andelman 3)
1) Exxon Research and Engineering, Annandale, New Jersey, USA
2) Materials Department, University of California, Santa Barbara, California, USA
3) Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel Aviv University,
Ramat Aviv, Israel
4) Polymer Dept., Weizmann Institute, Rehovot, Israel
Abstract: Although single surfactants rarely form vesicles spontaneously,
mixtures of two surfactants can lead to spontaneous vesicle formation. By
considering the curvature elasticity of the surfactant bilayer, we show
theoretically how the energetic stabilization of mixed vesicles can occur. In-
teractions between the two species (of the proper sign and magnitude) are
crucial to stabilizing these vesicles. These interactions lead to composition
asymmetries and effective spontaneous curvatures of the inner and outer
layers that are of equal and opposite signs.
Key words: _Vesicle; surfactant; selfassociation
I. Introduction phiphilic monolayers which, in the single surfactant
case, have the same spontaneous curvature [6].
Since vesicles rarely form as the equilibrium Since the two layers have curvature of opposite sign
structure of simple surfactant-water systems, non- (e.g., the inner one being concave with respect to
equilibrium methods, such as sonication of lameUar the water, and the outer one convex), the system is
liquid crystalline phases, are usually necessary to frustrated. Small vesicles, where the vesicle radius
obtain a metastable phase of vesicles, which may is of the order of the surfactant size, can be of lower
reequilibrate back into the multilamellar, liquid energy than fiat bilayer, as discussed in [9--12].
crystalline structure. Recently, however, Kaler et al. However, they may be of higher free energy than
[1] have reported a general method for producing small micelles. In this work, we consider the case of
equilibrium phases of vesicles of a controlled size. large vesicles and discuss their stability with respect
The vesicles form spontaneously upon mixing sim- to lamellar phases; this feature can be compared
ple surfactants with oppositely charged head with the experimental phase diagrams [13]. We find
groups. Most previous reports of spontaneous vesi- [7, 8] that the stabilization of the vesicles by surfac-
cle formation have also involved surfactant mixtures tant mixtures only occurs when interactions of the
[2--5]. Using the charge as a control parameter has surfactants is considered; ideal mixing of the two
both chemical and physical advantages since a wide components does not yield vesicles as the ground
variety of head group, counterion, and salt state. These results can be used to see how the in-
chemistries can be prepared and studied. teractions can be exploited to control and stabilize
In this paper, we use the concepts of curvature the vesicle phase.
elastic theory [6] to explain the stability of vesicles
formed in mixed surfactant systems. In systems
composed of a single surfactant, the curvature II. Mixed vesicles
energy of a bilayer dictates that the energy of a
phase of spherical vesicles is never lower than that In contrast to the situation for single amphiphiles,
of a multilamellar, liquid crystalline phase [7, 8]. where large vesicles are usually not energetically
This is because the bilayer is composed of two am- stable in comparison with fiat bilayers, vesicles
4 Progress in Colloid & Polymer Science, Vol. 84 (1991)
composed of two amphiphiles can have lower cur- interactions result in a local deformation of the
vature energies than fiat films. The curvature bond distances compared to their values for the
energy [6--8] per unit area of the vesicle is given by pure surfactants (which are assumed to have the
same bond lengths). We describe this by a quantity
Aij, which is the change in the bond length bet-
fc = 2K[(c + c0)2 + (c - -c i ) 2], (1)
ween surfactants at nearest-neighbor sites i and j.
Finally, there is an elastic-restoring force, with
where K is the bending elastic modulus [7, 8], q spring constant k:
and co are the spontaneous curvatures of the inner
and outer monolayers, and c is the actual curvature
H = ~. S ~ S j - B(1 -- SiSj)A 0 + - ~ A . (3)
of the inner layer. For the case of single surfactant
(ij~
systems, in the limit of small curvatures, co = c~. In
this case, the minimum of fc with respect to c im-
Here, B represents the strength of the coupling be-
plies that c = 0; fiat bilayers are the lowest bending
tween the composition and elastic degrees of
energy state. For mixed surfactants, constitutive
freedom. Equation (3) represents the compressible
relations for effective spontaneous curvatures of the
Ising model.
inner and outer layers, ci and co are needed.
The mean-field value of (A,) is found by
For simplicity, we consider a model where the
minimizing Eq. (3) with respect to (Ais):
spontaneous curvatures of films composed of each,
single surfactant are equal, cl = c2 , and define ¢/as
(A~j) = B(1 -- (S~Sj))/k ; (4)
the volume fraction of surfactant type "2" in the
system. In addition, we define ¢/~ and ¢/0 as the
the resulting expression for the free energy per sur-
volume fraction of surfactant "2" in the inner and
factant h is
outer layers, respectively. The composition differ-
ence between these two layers is rp = 1/2(¢/0 -- ~i),
B 2
with the constraint of fixed ~, --- 1/2(¢/0 + ~,~). h = l ( S , - (1 - ( s , sj ) 2 . (5)
We now describe a simple statistical model for the
surfactant head-head interactions which allows for
a unified treatment of the free energy of the system In random mixing, the nearest-neighbor correlation
including both the elastic, entropic, and interaction function (SiSj) can be found by weighting the two
contributions. Our basic assumption is that the in- possible values by the appropriate product of in-
teraction between head groups alone determines dependent probabilities for finding surfactants 1
the spacing between surfactants at the interfaces, and 2 at each site:
while the resulting compression of the surfactant
tails determines the spontaneous curvature of each ( s i s j ) = (1 - + C 2- ,(1 -
monolayer. (In [11], we shall relax this assumption.)
= ( 1 - - 2 ¢ / ) 2 . (6)
In this case, the spontaneous curvature depends
directly on the mean spacing between surfactant
Simple models for the packing of surfactant
head groups as a function of composition, ¢/.
molecules at a surface yield a spontaneous cur-
We first consider a monolayer with a repulsive in-
vature which depends linearly on the mean spacing
teraction +J between like head groups, and an at-
between polar head groups. Within the model of
tractive interaction, - J between opposite head
the previous section, the change in the spon-
groups. This suggests an Ising model description
taneous curvature depends on (Aij), and hence on
for the energy H of a two-component mixture:
I s i s j l :
H = ~ JS~Sj, (2 )
/ / ( 1 - - ( S i S j ) ) = - - (7)
- - c ( 0 ) = 7
where the sum over (i]) includes only nearest
neighbor pairs. The constituents are labeled by i, The parameter ]/is of order a -1, where a is a micro-
and Si = +1 (--1) denotes the presence of surfac- scopic length. The precise value of ] /can be obtain-
tant (2). Furthermore, the attractive or repulsive ed, although it is somewhat model specific [11].