Micellar interactions in water-in-oil microemulsions. 2. Light scattering determination of the second virial coefficient

Brunetti, S.; Roux, D.; Bellocq, A. M.; Fourche, Georges; Bothorel, P.

doi:10.1021/j100229a022

Cited by 122 publications

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“…All those results concerning microemulsion domain configuration, electrical conductivity and viscosity are mutually consistent, generalize previous findings by Hell et al, [4][5][6][7][8][9][10][11], are in agreement with data reported in the literature by other groups of authors, , and may receive an interpretation relying on the influence of the chemical structure of the system constituents upon the internal organization of and interactions in microemulsion-type media [34][35][36][37]. They will be fully reported, analyzed and commented upon in forthcoming detailed articles.…”

supporting

confidence: 94%

Water/ionic surfactant/alkanol/hydrocarbon systems. Realms-of-existence and transport properties of microemulsion type media

Clausse

Zradba

Nicolas-Morgantini

1985

Colloid & Polymer Sci

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From a thorough study of many systems incorporating water, the ionic surfactant sodium dodecylsulfate, straighter or branched alkanols and aliphatic or aromatic hydrocarbons, it clearly appears that the molecular structure of the alkanol used as the cosurfactant is the composition factor that primarily determines the configuration of the microemulsion domain and, correlatively, the type of the microemulsion electroconductive and viscous behavior.Key words: Microemulsion(s), phase diagram(s), viscosity, electrical conductivity, water, sodium dodecylsulfate, straight alkanol(s), branched alkanol(s), aliphatic hydrocarbon(s), aromatic hydrocarbon(s).The realms-of-existence of monophasic, stable, fluid, transparent and isotropic media, (so-called "microemulsions" [1]), were delineated, at T = 25 ~ for a great number of systems incorporating water, sodium dodecylsulfate, straight or branched alkanols with number of carbons ranging from 2 to 10, and aliphatic, (n-octane, n-dodecane, n-hexadecane), or aromatic, (benzene, toluene), hydrocarbons. It has thus been possible to evidence the influence of different composition factors upon the general configuration of the microemulsion domain, e. g. straight alkanol number of carbons, alkanol isomery, aliphatic hydrocarbon chain-length, and aliphatic hydrocarbon-aromatic hydrocarbon substitution [2][3].It clearly appears from this study that, in any case, the three-dimensional microemulsion domain is the volumic extension of the realm-of-existence of the water/surfactant/alkanol micellar solutions. The micro-1) Present addresses: A. Zradba, Ecole Normale Sup~rieure de Casablanca, Avenue Victor Hugo, Casablanca, Maroc (Morocco).L. Nicolas-Morgantini, L'Or~al, 1, Avenue Saint Germain, 93600 Aulnay-sous-Bois (France). W950emulsion domain configuration is influenced, primarily, by the alkanol molecular structure, and, to a lesser degree, by that of the hydrocarbon. As a general rule, the microemulsion domain existing in the phase tetrahedron of systems incorporating long straight alkanols, (number of carbons no1 > 6), appears to consist of two disjoined volumes, V1 and V2, respectively built on the regions L1 and L2 corresponding, in the water/ surfactant/alkanol phase diagram, to direct and inverse ternary micellar solutions. Per contra, the microemulsion domain of systems incorporating short straight alkanols, (nc~ < 3), forms in the phase tetrahedron an all-in-one-block volume built on the "monophasic" area that exists in the water/surfactant/alkanol phase diagram, as the result of the merging of the L1 and L2 regions. In the case of medium straight alkanols, (3 < nca < 6), the microemulsion domain also forms an allin-one-block volume but exhibits configuration irregularities that reflect peculiarites of the water/surfactant/alkanol "monophasic" area.For the four systems water/sodium dodecylsulfate/ C4 to C7 straight alkanols/n-dodecane, details of the microemulsion domain configuration were obtained from systematic determinations of the microemulsion

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supporting

confidence: 94%

Water/ionic surfactant/alkanol/hydrocarbon systems. Realms-of-existence and transport properties of microemulsion type media

Clausse

Zradba

Nicolas-Morgantini

1985

Colloid & Polymer Sci

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“…In this study, d h values at three ω values are reported. The system water/(TX-100 + n-alkanol)/n-heptane is not stable for a wide range of ω in the presence of additives as in the H 2 O/AOT/heptane microemulsion system (30)(31)(32). For the present system, ω could only be varied within a narrow range of 20-30.…”

Section: Effect Of [Water]/[tx-100] Ratio ωmentioning

confidence: 87%

Dispersed Molecular Aggregates

Panda

Moulik

Bhowmik

et al. 2001

Journal of Colloid and Interface Science

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“…The slow polymerization is also found in systems with strong base-acid complexes SDS/ BAc and STPO/BAc, known to form close packed structures (or rigid surface film). 32 The distribution coefficient for BAc{(BA/water, 1/l(v/v)) estimated to be 88/12 (the weight ratio)} indicates that BAc prefers more the 93 monomer (microdroplet) phase and so its reaction with growing radicals (chain transfer events) takes place. The predominant location of STPO and SDS in the interfacial layer promotes interactions with BAc.…”

Section: Polymerization Ratementioning

confidence: 99%

Microemulsion Polymerization of Butyl Acrylate. Effect of Radical Scavenger and Formation of Primary Radicals

Capek

Juraničová

2000

Polym J

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:Microemulsion polymerizations of butyl acrylate initiated by dibenzoyl peroxide in the presence of a radical scavenger (RS)(stable radicals: an oil soluble RS: 4-stearoyloxy-2,2,6,6-tetramethyl piperidine-1-oxyl (STPO) and water soluble RS: 4-hydroxy-2,2,6,6-tetramethyl piperidine-1-oxyl (HTPO)}were investigated. STPO and HTPO decreased the rate of polymerization and the decrease was more pronounced with STPO. Inorganic salts and organic additives decreased the rate of polymerization. The shift of the maximum rate of polymerization to lower conversion by increasing temperature and addition of several additives was attributed to increase of particle number and decrease of monomer concentration at the reaction loci. The decrease of the particle size in the presence of RS is attributed to retardation of particle growth. A close packed structure at the droplet surface promoted by current additives acts as a barrier for entering radicals. The larger overall activation energy in runs with STPO is discussed in terms of a depressed entry ofradicals into microdroplets.KEY WORDS Microemulsion / Butyl Acrylate/ Polymerization/ Tetramethyl Piperidine-1-oxyl Radical Scavenger/ Inorganic Salts/ Rate of Polymerization/ Polymer Particles/ In the case of microemulsion polymerization initiated by the oil-soluble initiator, there are two main approaches for the production of primary radicals : 1 -3 1) in the monomer swollen micelles or polymer particles radicals desorb to the aqueous phase and 2) in the aqueous phase radicals are generated from the fraction of the oilsoluble initiator dissolved in water. -6 A partly watersoluble initiator such as a,a'-azobis(isobutyronitrile) (AIBN) forms primary radicals in both the aqueous phase and in the monomer-swollen micelles. In the case of highly hydrophobic initiator the formation of radicals from the fraction of initiator dissolved in the aqueous phase is negligible, as well as exit of hydrophobic primary radicals into the aqueous phase. Microemulsion and miniemulsion polymerizations initiated by hydrophobic initiators such as dibenzoyl peroxide (DBP) or lauroyl peroxide (LPO) are reported to be relatively fast. 1 · 2 • 7 The very low water solubility of hydrophobic initiator (DBP, LPO, etc.) and radical fragments propose a very low rate of polymerization (ca. by two orders in magnitude lower than that for peroxodisulfate initiated polymerization). The strong cage effect within the microdroplets or latex particles depresses the formation of radicals in the monomer phase. However, the rate of DBP-initiated polymerization was ca. 5 times smaller than the water-soluble peroxodisulfate initiated polymerization (polymerizations carried out under the same reaction conditions). Thus, the polymerization behavior is not properly described by two reaction approaches : 1) water-phase initiation and 2) desorption of primary (monomeric) radicals formed in the microdroplets in the aqueous phase.The non-linearity between the molecular weights of the polystyrene (much below 10 5 ) and laser r...

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Micellar interactions in water-in-oil microemulsions. 2. Light scattering determination of the second virial coefficient

Cited by 122 publications

References 0 publications

Water/ionic surfactant/alkanol/hydrocarbon systems. Realms-of-existence and transport properties of microemulsion type media

Water/ionic surfactant/alkanol/hydrocarbon systems. Realms-of-existence and transport properties of microemulsion type media

Dispersed Molecular Aggregates

Microemulsion Polymerization of Butyl Acrylate. Effect of Radical Scavenger and Formation of Primary Radicals

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