Comparative investigation of cetyltrimethylammonium bromide micelles in water and formamide by nuclear magnetic relaxation

Belmajdoub, A.; Elbayed, Karim; Brondeau, J.; Canet, Daniel; Rico, I.; Lattes, Armand

doi:10.1021/j100323a049

Cited by 34 publications

(39 citation statements)

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“…Under these conditions, Eriksson et al (13) used the two-step model (12), which assumes two correlation times, one to describe rapid local motion and another to describe a slower motion over distances of the order of the dimensions of the micellar aggregates. It was further assumed that the spectral density function J ( o ) is a sum of two Lorentz functions (9-1 3), 75, f 7, [6] J ( o ) = S2 Typical values of T', for surfactant micelles appear to be 1-10 ns (8)(9)(10)(11)(12), while values of 7: and S will be dependent on the solubilizate. For example, for benzene-d6 and cyclohexane-d12, S values of approximately 0.08 and 0.01, respectively, have been reported (13).…”

Section: Deuterium Nmr Relaxationmentioning

confidence: 99%

NMR studies of hydrocarbons solubilized in aqueous micellar solutions

Wasylishen¹,

Kwak²,

Gao³

et al. 1991

Can. J. Chem.

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. 69, 822 (1991).Information concerning the solubilization of hydrocarbons in ionic surfactant micelles was obtained from 'H NMR relaxation, 'H NMR chemical shifts, and 'H NMR paramagnetic relaxation measurements. The rotational motion of deuterated hydrocarbons, which is related to the micellar microviscosity at the location of the hydrocarbons, was probed by ' H NMR relaxation. The relaxation data are interpreted using both the two-step and the single-step models, and the results are discussed in terms of the micellar microviscosity and the location of the hydrocarbons in micelles. The location of the hydrocarbons in micelles was further investigated by determining the aromatic ring current-induced 'H chemical shifts along the surfactant alkyl chain and by comparing the 'H spin-lattice relaxation enhancement of the hydrocarbons and the surfactant alkyl chain, induced by ~n ' ' on the micellar surface. The hydrocarbons used include benzene, naphthalene, acenaphthalene, triphenylene, cyclohexane, cyclododecane, and tert-butylcyclohexane and the surfactants studied are hexadecyl-, tetradecyl-, and dodecyltrimethylammonium bromide; hexadecyl-, tetradccyl-, and dodecylpyridinium halide; and sodium dodecyl sulfate. The results indicate that the micellar microviscosity at the location of saturated hydrocarbons is approximately 5 cP for both the cationic and anionic micelles, whereas the micellar microviscosity at the location of unsaturated hydrocarbons is much higher. The unsaturated hydrocarbons are found to reside primarily near the surfactant headgroup in the cationic micelles, but are distributed evenly throughout the anionic SDS micelles. The saturated hydrocarbons appear to be located in the interior of the micelles. 822 (1991). Utilisant la relaxation RMN du 'H, les dCplacements chimiques en RMN du 'H et des mesurcs de relaxation paramagnktique en RMN du 'H, on a obtenu de I'information concernant la solubilisation d'hydrocarbures dans des micelles d'agents de surfaceioniques. Pour Ctudier le mouvement de rotation des hydrocarbures deutCrCs qui est reliC la microviscositC micellaire au point de location des hydrocarbures, on a fait appel h la relaxation en RMN du 'H. On a interprCte les donnCes de relaxation utilisant les modkles en une ainsi qu'en deux Ctapes et on discute des rCsultats en fonction de la microviscositC micellaire et de la position des hydrocarbures dans les micelles. On a rCalisC une Ctude plus approfondie de I'influence de la position des hydrocarbures dans les micelles en determinant les dCplacements chimiques induits par le courant du noyau aromatique le long de la chaine alkyle de I'agent de surface et en comparant les augmentations des relaxations spin-reseau du 'H des hydrocarbures et de la chaine alkyle de I'agent de surface qui sont induites par du ~n ' .~ sur la surface micellairc. Les hydrocarbures utilisks sont le benzene, le naphtalkne, I'acCnaphtalkne, le triphknylkne, le cyclohexane, le cyclododCcane et le terl-butylcyclohexane alors que les agents de surface ttudiCs sont les ...

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Section: Deuterium Nmr Relaxationmentioning

confidence: 99%

NMR studies of hydrocarbons solubilized in aqueous micellar solutions

Wasylishen¹,

Kwak²,

Gao³

et al. 1991

Can. J. Chem.

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“…To our knowledge, the first report of amphiphile selfassembly in a non-aqueous solvent at ambient temperature was by Ray in 1969 for ethylene glycol. 19 The effect of different non-aqueous solvents on liquid crystalline mesophase formation has previously been reported for protic solvents such as formamide, [20][21][22][23][24][25][26][27][28][29][30][31] N-methylformamide, 28 glycerol, 20,[26][27][28] ethylene glycol, 19,27 propylene glycol, 20 butylene glycol, 20 N-methylacetamide 21 and hydrazine, 21,31 and the aprotic solvents of N-methylsydnone 32 and dimethylformamide. 20,21,28,31 The use of non-aqueous self-assembly solvents was reviewed by Ward and du Reau in 1993.…”

Section: Introductionmentioning

confidence: 97%

“…33 A series of papers has been written by Auvray, Rico and Lattes et al on the behaviour of amphiphiles such as hexadecyltrimethylammonium bromide (CTAB), cetylpyridinium bromide (CPBr) and sodium dodecyl sulfate (SDS) in various polar solvents, including formamide, ethylene glycol, glycerol and N-methylformamide. [23][24][25][26][27][28]32,[34][35][36][37] Many new ILs can be created from different cation and anion combinations, which allows the possibility of tailoring self-assembly solvents with specific desired properties. Previously, changing the properties of a self-assembly system was effectively limited to modifying the amphiphile.…”

Section: Introductionmentioning

confidence: 99%

Ionic liquids as amphiphile self-assembly media

2008

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In recent years, the number of non-aqueous solvents which mediate hydrocarbon-solvent interactions and promote the self-assembly of amphiphiles has been markedly increased by the reporting of over 30 ionic liquids which possess this previously unusual solvent characteristic. This new situation allows a different exploration of the molecular "solvophobic effect" and tests the current understanding of amphiphile self-assembly. Interestingly, both protic and aprotic ionic liquids support amphiphile self-assembly, indicating that it is not required for the solvents to be able to form a hydrogen bonded network. Here, the use of ionic liquids as amphiphile self-assembly media is reviewed, including micelle and liquid crystalline mesophase formation, their use as a solvent phase in microemulsions and emulsions, and the emerging field of nanostructured inorganic materials synthesis. Surfactants, lipids and block co-polymers are the focus amphiphile classes in this critical review (174 references).

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“…There has recently been much research dealing with the effects of nonaqueous polar solvents on the formation of cationic micelles (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). Micel!e or liquid crystal formation has been reported to occur in such solvents as hydrazine (3,4), glycerol (5,6), ethylene glycol (7,8), and formamide (9)(10)(11)(12)(13)(14)(15)(16)(17)(18), where all of the aforementioned solvents have high cohesive energy, dielectric constant, and a high degree of hydrogen bonding. Evans and co-workers (19) have indicated that the ability of a solvent to form hydrogen bonds is a necessary condition of micelle formation.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic properties of micellization of sodium dodecyl sulfate in binary mixtures of ethylene glycol with water

Gracie¹,

Turner²,

Palepu³

1996

Can. J. Chem.

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Micellar properties of sodium dodecyl sulfate (SDS) in aqueous mixtures of ethylene glycol (EG) were determined using techniques such as conductivity, density, EMF, surface tension, viscosity, ultrasonic velocity, and spectroscopy (fluorescence). The effective degree of disssociation of micelles ( a ) was determined using three different methods. Thermodynamics of micellization were obtained from the temperature dependence of critical micelle concentrations (cmc) values. The difference in Gibbs energies of micellization ( A G~) of SDS, between water and mixed solvent systems, was calculated to evaluate the influence of cosolvent on the micellization process. Surfactant aggregation numbers (N,) obtained from static fluorescence quenching methods indicated a decrease in the aggregation numbers with increasing concentration of ethylene glycol in the binary solvent mixtures. In addition, the micropolarity of the micellar interior was determined from the pyrene I,II:, ratios. These values were consistent with a decrease in the micropolarity surrounding the probe molecule as the EG content in the solvent mixture was increased.

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Comparative investigation of cetyltrimethylammonium bromide micelles in water and formamide by nuclear magnetic relaxation

Cited by 34 publications

References 0 publications

NMR studies of hydrocarbons solubilized in aqueous micellar solutions

NMR studies of hydrocarbons solubilized in aqueous micellar solutions

Ionic liquids as amphiphile self-assembly media

Thermodynamic properties of micellization of sodium dodecyl sulfate in binary mixtures of ethylene glycol with water

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