Study of dynamical and structural properties of microemulsions by chemical physics methods

Bellocq, A. M.; Biais, J.; Clin, B.; Lalanne, P.; Lemanceau, Bernard

doi:10.1016/0021-9797(79)90060-2

Cited by 57 publications

(18 citation statements)

References 26 publications

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“…Bellocq et al in a 1H-based spin-lattice relaxation study of the butanol-toluene-SDS-water system concluded that all observed spin relaxation data displayed very regular trends with concentration for all components, and suggested on this basis that one most probably has a continuous transition between different modes of aggregation in this system [21]. While this conclusion is most probably correct, the organization- Fig.…”

Section: Microemulsionsmentioning

confidence: 80%

NMR measurements on microemulsions

Stilbs

Lindman

1984

Surfactants, Micelles, Microemulsions and Liquid Crystals

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Fourier transform Nuclear Magnetic Resonance studies, providing information on relative molecular self-diffusion coefficients and nuclear spin relaxation rates in microemulsions, have led to a reassessment of the prevalent ,,droplet" conception of the molecular organization in microemulsions. An O/W-organized system (e. g. a micellarlike) is necessarily characterized by rapid water diffusion and slow surfactant (and hydrocarbon solubilizate) diffusion. W/O systems must likewise exhibit slow water and surfactant diffusion, while the diffusion processes in the continuous hydrocarbon phase remain rapid. The experimentally observed diffusion behaviour in some microemulsion types (e. g. Aerosol OT-water-hydrocarbon) can, essentially throughout the entire extensive composition stability range, be reconciled with a distinct water-in-oil model while the dynamic properties on the molecular level of others (e. g. medium-chain alcohol cosurfactant types), resemble over wide concentration ranges those of partially aggregated liquids. As clearly shown by our multicomponent self-diffusion data, the degree of molecular organization over large composition regions of cosurfactant microemulsion systems is much lower than that in miceUar solutions or normal emulsions, for example. Spin relaxation data indicate, on the other hand, that some supramolecular aggregation prevails during the (organizational) timescale of these experiments (c. 100 ps). In a local frame, this residual organization is probably similar to that found in micelles containing solubilized alcohols or hydrocarbons.

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Section: Microemulsionsmentioning

confidence: 80%

NMR measurements on microemulsions

Stilbs

Lindman

1984

Surfactants, Micelles, Microemulsions and Liquid Crystals

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“…The phase diagram of the system NaDDS+H 2 0+n-Butanol+Toluene been extensively described in the literature (11,12). Further, the interfacial tensions of this system when it separates into two or three phases has been reported, depending on the concentration of the added electrolyt, NaCl, Tables I and II.…”

Section: Resultsmentioning

confidence: 97%

“…In the current liter ature, almost all the low or ultra-low yij values have been mea sured by using the "spinning drop" method (8)(9)(10). The purpose of this study is to report comparative data of a system (11,12), ί·£· NaDDS (Ci2^580^3) +H 2 0+n-Butanol+Toluene, by using the pendant drop method. Further, the pendant drop method is used to determine the yij of various ternary systems.…”

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confidence: 97%

Interfacial Tension of Aqueous Surfactant Solutions by the Pendant Drop Method

Birdi

Stenby

1984

ACS Symposium Series

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The low interfacial tensions between two liquids have been measured for different systems by using the pendant drop method. In the case of the quaternary system: C 12 H 25 SO 4 Na+H 2 O+n-Butanol+Toluene, the interfacial data as measured by pendant drop method are compared with reported literature data, using other methods (with varying NaCl concentration). In order to understand the role of co-surfactant, ternary systems were also investigated. The pendant drop method was also used for measuring the interfacial tension between surfactant-H 2 O/n-alcohol (with number of carbon atoms in alcohol varying from 4-10). The interfacial tension variation was dependent on both the surfactant and alcohol.In the current literature one finds that the knowledge of interfacial tension, Yi j, at liquids-liquidj is of much importance in many different systems, £._g. emulsions, microemulsions, ehnanced oil recovery etc.If one considers a system consisting of: water (with or without added electrolyte) + oil + surfactant (with or without a cosurfactant) at equilibrium, there will most likely be present more than two phases (due to the formation of emulsion or microemulsion). The determination of the interfacial tension, Yi j, between the two liquid phases is, therefore, of much importance, in order to understand the forces which stabilize these emulsions or microemulsions. The interfacial tension can be measured by using a variety of methods, as described in detail in surface chemistry text-books (1-3). If the magnitude of Yij is of the order of few mN/ m (=dyne/ cm), then the methods generally used are: Wilhelmy plate method or the drop volume (or weight) method (1-4). However, in certain systems ultra-low (or low) interfacial tensions have been reported. Since these low values are reported to be essential in order to mo-0097-6156/ 84/ 0253-0329S06.00/ 0

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“…Cela signifie qu'elles seraient constitutes de microdomaines aqueux etde microdomaines organiques dispos~s de faqon al~atoire et s~par~s les uns des autres par des films tr~s flexibles de molecules amphiphiles. Diverses donees exp~rimentales tendent ~t valider ce module de structure, [11][12][13][14][21][22][23][24][25][26]. Par ailleurs, il semble acquis que, lorsque leur teneur en eau est faible, les micro~mulsions form6es avec un surfactant ionique contiennent, non pas de v~ritables microgouttelettes "inverses", mais des agr~gats de molecules de surfactant hydrat~es, [27][28][29][30].…”

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“…Par ailleurs, il semble acquis que, lorsque leur teneur en eau est faible, les micro~mulsions form6es avec un surfactant ionique contiennent, non pas de v~ritables microgouttelettes "inverses", mais des agr~gats de molecules de surfactant hydrat~es, [27][28][29][30]. Enfiin, il a ~t~ m~me sugg~r~, [12], que les micro~mulsions tr~s fiches en surfactant et cosurfactant, (donc pauvres en eau et en hydrocarbure), poss~deraient une structure locale de type lamellaire.…”

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Influence de divers param�tres de constitution et de composition sur la configuration du domaine d'existence et certaines propri�t�s de microemulsions quaternaires monophasiques

Nicolas-Morgantini

Clausse

Poquet³

1986

Colloid & Polymer Sci

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Macroscopically homogeneous, stable, fluid, generally optically transparent and isotropic media (currently called "microemulsions") may be formed by adequately mixing together water, a hydrophobic hydrocarbon, ("oil"), and suitable amphiphilic substances. The microemulsion domains of numerous systems incorporating water, sodium dodecylsulfate, various straight or branched alkanols and various aliphatic or aromatic hydrocarbons were delineated at T = 25 ~ It has thus been possible to bring out the influence of several composition factors upon microemulsion domain configuration, i. e. straight alkanol number of carbon atoms, alkanol isomery, normal aliphatic hydrocarbon number of carbon atoms, aliphatic hydrocarbon-aromatic hydrocarbon substitution. The existence of two main kinds of water/ionic surfactant/alkanol/hydrocarbon systems, according as the microemulsion realm-of-existence in the phase tetrahedron consists of two disjoined volumes, ("long" alkanols), or forms an all-in-one block volume, ("short" alkanols), can well be correlated with the existence of striking dissimilarifles in certain transport properties of microemulsions, such as electrical conductivity or viscosity. For some "short" alkanols, (e. g. 1-pentanol or 2-pentanol), the microemulsion domains exhibits strange configuration irregularities. Results gained from studies of microemulsion electroconductive and viscous behavior and of cyclohexene-2-one-lphotodimerization in microemulsions tend to indicate that these configuration irregularities define certain ranges of system composition that correspond to microemulsions possessing an exotic structure.Key words: Water, sodium dodecylsulfate, straight and branched alkanols, afiphatic and aromatic hydrocarbons, cyclohexene-2-one-1, microemulsion(s).Des milieux tr~s divers par le nombre et la nature des phases qui les composent, lorsque l'~quilibre thermodynamique est atteint, peuvent ~tre form,s en m~langeant de l'eau, (ou une solution saline aqueuse), un liquide hydrophobe tel qu'un hydrocarbure aliphatique ou aromatique et une (ou plusieurs) substance

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Study of dynamical and structural properties of microemulsions by chemical physics methods

Cited by 57 publications

References 26 publications

NMR measurements on microemulsions

NMR measurements on microemulsions

Interfacial Tension of Aqueous Surfactant Solutions by the Pendant Drop Method

Influence de divers param�tres de constitution et de composition sur la configuration du domaine d'existence et certaines propri�t�s de microemulsions quaternaires monophasiques

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