Rôle de l'alcool dans les microemulsions. II. Volumes et capacités calorifiques molaires apparents du système eau + dodécylsulfate de sodium + isopropanol à 298,15 K

Majer, Vladimı́r; Roux, A. J.; Roux-Desgranges, G.; Viallard, André

doi:10.1139/v83-025

Cited by 22 publications

(3 citation statements)

References 10 publications

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“…assuming that all sorbed SDS has a density, d, similar to that in aqueous solutions [29]. The polymer densities, q p , of gels AA1-AA5 are 249 AE 10, 422 AE 18, 202 AE 8, 241 AE 7 and 364 AE 28 kg m À3 , respectively.…”

Section: Kinetic Studiesmentioning

confidence: 99%

Diffusion coefficients of sodium dodecyl sulfate in water swollen cross-linked polyacrylamide membranes

Valente

Miguel

Lobo

2002

European Polymer Journal

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Diffusion of aqueous sodium dodecyl sulfate (SDS) across cross-linked polyacrylamide hydrogel membranes has been studied by electrical conductivity measurements. Initial rapid sorption of SDS (as unimer) into the membranes is observed. The effect of SDS concentration, and of cross-linker fraction on the degree of swelling of the gels is studied and associated with binding of the surfactant to the polymer, with surface bound water suggested to be involved in these interactions. Below the surfactant critical micelle concentration, volume collapse of less cross-linked membranes is observed, and associated with aggregate formation. Fluorescence measurements using pyrene as a probe show that micellar aggregates do not diffuse through the membrane, and only overall unimer diffusion is observed. The effect of cross-linking on the diffusion process is discussed.

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Section: Kinetic Studiesmentioning

confidence: 99%

Diffusion coefficients of sodium dodecyl sulfate in water swollen cross-linked polyacrylamide membranes

Valente

Miguel

Lobo

2002

European Polymer Journal

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“…assuming that all sorbed surfactant has a density, d, similar to that in aqueous solutions [21]. The polymer densities, q, and the swelling degrees, Q, are taken from Table 1.…”

Section: Theoretical Approach To Diffusion Coefficientsmentioning

confidence: 99%

Sorption/diffusion behaviour of anionic surfactants in polyacrylamide hydrogels: from experiment to modelling

Valente

Polishchuk²,

Miguel

et al. 2003

European Polymer Journal

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The sorption and diffusion processes of anionic surfactants with different chain length through polyacrylamide hydrogels with low swelling degree have been studied by electrical conductivity measurements. The multicomponent equilibrium equation has been used to model the sorption isotherms of different anionic surfactant in the hydrogels. Such isotherms show that initial rapid sorption of unimer surfactant into the membranes occurs, suggesting that nonfreezing water can be involved in these interactions. In aqueous solution, at concentrations near and above the critical micelle concentration an anti-co-operative region is found. The diffusion coefficients of the anionic surfactants inside the hydrogel matrix show that the mobility of diffusing surfactant entities is dependent on cross-linker concentration and chain length. The Cukier hydrodynamic model and the free volume theory as modified by Peppas and Reinhart were applied to explain the dependence of the diffusion coefficients of surfactant on surfactant concentration inside the hydrogel. The hydrodynamic model was applied with success to the more hydrophilic surfactant, sodium 1-octanesulfonate, showing that the diffusion coefficients, D, increase when the resistance to hydrodynamic medium decreases; when the surfactant chain length increases (sodium dodecyl sulfate and sodium 1-hexadecane sulphonate) the variation of D with the free volume can only be understood considering the sieving effect produced by the surfactant inside gel.

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“…Incidentally, in recent years, the amount of reliable data on such functions has increased remarkably (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). At the same time, theoretical models have been developed to simulate the trends in the transfer functions and extract, from the data, fundamental thermodynamic parameters for the mixed micelles (18)(19)(20)(21)(22)(23)(24)(25)(26)(27).…”

Section: Introductionmentioning

confidence: 99%

Volumes and heat capacities of transfer of ammonium salts from water to aqueous octyldimethylamine oxide at 25 °C

Hétu¹,

Desnoyers²

1988

Can. J. Chem.

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. 66, 767 (1988).The effect of an additive on a water-surfactant system can be studied through thermodynamic functions of transfer of the additive from water to aqueous solutions of the surfactant. These thermodynamic functions often go through extrema in the region of the critical micellar concentration (cmc) of the surfactant. As it can be shown with a simple chemical equilibrium model, the general shape of the transfer functions is primarily related to the pair-wise hydrophobic interactions between the additive and the surfactant monomers, to a shift in the monomer-micelle equilibrium and to the distribution of the additive between the aqueous phase and the micelles. Medium and electrostatic effects are also possible, especially with ionic systems. To separate these effects and identify the salts which distribute themselves in the micelles, the volumes and heat capacities of transfer of hydrophobic ammonium salts from water to aqueous solutions of dimethyloctylamine oxide have been investigated. The short chain salts have only a small effect on monomer-micelle equilibrium by salting out the monomers, whereas the more hydrophobic ones participate also to the micellization process, shifting more strongly the surfactant monomer-micelle equilibrium.DANIEL HCTU et JACQUES E. DESNOYERS. Can. J. Chem. 66, 767 (1988).L'effet d'un additif sur un systkme eau-tensioactif peut Ctre CtudiC par le biais des fonctions de transfert de l'additif de l'eau aux solutions aqueuses du tensioactif. Ces fonctions thermodynamiques passent souvent par un extremum dans la region de la concentration micellaire critique (cmc) du tensioactif. Comme il peut Ctre dCmontrC B l'aide d'un modkle simple d'tquilibre chimique, l'allure gCnCrale des fonctions de transfert est principalement relike aux interactions hydrophobes par paires entre les monomkres de l'additif et du tensioactif, au dCplacement de 1'Cquilibre monomkres-micelles du tensioactif, ainsi qu'i la distribution de l'additif entre la phase aqueuse et les micelles. Des effets de milieu ainsi qulClectrostatiques peuvent aussi jouer un r61e important, particulikrement dans le cas de systkmes ioniques. Afin de sCparer ces effets et d'identifier les sels qui participent B la micellisation, les volumes et capacitCs calorifiques dc transfert de sels hydrophobes d'ammonium de I'eau aux solutions aqueuses d'oxyde dloctyldimCthylamine ont CtC investiguks. Les sels a courtes chaines ont seulement un petit effet sur 1'Cquilibre monomkres-micelles du tensioactif, dh a un effet de relargage, alors que les sels B plus longues chaines participent en plus i la micellisation, dCpla~ant davantage 1'Cquilibre du tensioactif.

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Rôle de l'alcool dans les microemulsions. II. Volumes et capacités calorifiques molaires apparents du système eau + dodécylsulfate de sodium + isopropanol à 298,15 K

Cited by 22 publications

References 10 publications

Diffusion coefficients of sodium dodecyl sulfate in water swollen cross-linked polyacrylamide membranes

Diffusion coefficients of sodium dodecyl sulfate in water swollen cross-linked polyacrylamide membranes

Sorption/diffusion behaviour of anionic surfactants in polyacrylamide hydrogels: from experiment to modelling

Volumes and heat capacities of transfer of ammonium salts from water to aqueous octyldimethylamine oxide at 25 °C

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