FT-IR Investigation of the Urea State in AOT Reversed Micelles

Calvaruso, Giuseppe; Minore, A.; Liveri, Vincenzo Turco

doi:10.1006/jcis.2001.7878

Cited by 39 publications

(37 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, a wide investigation of the state of urea within dry sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and lecithin reversed micelles has been reported [12][13][14]. The experimental data are consistent with the hypothesis that this substance is quite uniformly distributed between AOT and lecithin reversed micelles and encapsulated as small molecular clusters within their hydrophilic micellar cores.…”

Section: Introductionsupporting

confidence: 76%

“…An analysis of the AOT and lecithin CH stretching band (2800-3000 cm −1 ) leads to the conclusion that no significant change in its shape, position, and intensity occurs as a function of R. This band being sensitive to the aggregation state and lateral packing order of the surfactant chains as well as to their conformational dynamics, the observed behavior indicates that acrylamide confinement in AOT and lecithin reversed micelles does not significantly modify the structure and dynamics of surfactant hydrocarbon tails [12,24].…”

Section: Ftir Spectramentioning

confidence: 70%

“…The state of confined acrylamide has been investigated by FTIR and 1 H NMR spectroscopy because it has been proved that these techniques are well suited to gain information simultaneously on the environments of spatially separated moieties of both solubilizate and surfactant molecules and consequently on the structural arrangement of solubilizatecontaining reversed micelles [11,12,17].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Physicochemical investigation of acrylamide solubilization in sodium bis(2-ethylhexyl)sulfosuccinate and lecithin reversed micelles

Calandra

Giordano

Ruggirello

et al. 2004

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

Section: Introductionsupporting

confidence: 76%

Section: Ftir Spectramentioning

confidence: 70%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Physicochemical investigation of acrylamide solubilization in sodium bis(2-ethylhexyl)sulfosuccinate and lecithin reversed micelles

Calandra

Giordano

Ruggirello

et al. 2004

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

“…In the literature, [32,33,[43][44][45] several studies on the symmetric S=O stretching band and the asymmetric stretching mode have been reported in aqueous reverse micelles, such as water/AOT/ isooctane, cyclohexane, n-heptane or benzene and in urea/ AOT/CCl 4 . These studies showed that upon the addition of water to the reverse-micelle system, there was a shift in the symmetric S=O (n s SO 3 ) stretching band to lower frequencies (from 1051.4 to 1045 cm À1 when the W 0 values increased from zero to 20; the greatest changes were observed to at W 0 < 3).…”

Section: Symmetric S=o Stretching Band (N S So 3 )mentioning

confidence: 99%

“…Since the S=O stretching bands are very sensitive to H-bond interactions between the polar solvents and the SO 3 À group, and to electrostatic interactions between the Na + counterion and the SO 3 À group, [25,31,32,[43][44][45] we have decided to explore this region to obtain more information about the different polar solvent-AOT polar head interactions.…”

Section: Aot Sulfonate Stretching Regionmentioning

confidence: 99%

Effect of the Constrained Environment on the Interactions between the Surfactant and Different Polar Solvents Encapsulated within AOT Reverse Micelles

et al. 2009

View full text Add to dashboard Cite

Herein, we report a study of the interactions between different nonaqueous polar solvents, namely, ethylene glycol (EG), propylene glycol (PG), glycerol (GY), dimethylformamide (DMF), and dimethylacetamide (DMA), and the polar heads of sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT) in nonaqueous AOT/n-heptane reverse micelles. The goal of our study is to gain insights into the unique reverse-micelle microenvironment created upon encapsulation of these polar solvents. For the first time, the study is focused on determining which regions of the AOT molecular structure are involved in the interactions with the polar solvents. We use FTIR spectroscopy--a noninvasive technique--to follow the changes in the AOT C=O band and the symmetric and asymmetric SO(3)(-) vibration modes upon increasing the content of polar solvents in the micelles. The results show that GY interacts through H bonds with the SO(3)(-) group, thereby removing the Na(+) counterions from the interface remaining in the polar core of the micelles. PG and EG interact through H bonds, mainly with the C=O group of AOT, penetrating into the oil side of the interface. Thus, they interact weakly with the Na(+) counterion, which seems to be close to the AOT sulfonate group. Finally, DMF and DMA, encapsulated inside the reverse micelles, interact neither with the C=O nor with the SO(3)(-) groups, but their weakly bulk-associated structure is broken because of the interactions with Na(+). We suggest that DMF and DMA can complex the Na(+) ions through their carbonyl and nitrogen groups. Hence, our results do not only give insights into how the constrained environment affects the bulk properties of polar solvents encapsulated within reverse micelles but--more importantly--they also help us to answer the tricky question about which regions of the AOT moiety are involved in the interactions with the polar solvents. We believe that our results show a clear picture of the interactions present at the nonaqueous reverse-micelle interface; this is important because these media are interesting nanoreactors for heterogeneous chemistry, templates for nanoparticles, and models for membranes.

show abstract

Effect of the Cationic Surfactant Moiety on the Structure of Water Entrapped in Two Catanionic Reverse Micelles Created from Ionic Liquid‐Like Surfactants

Villa¹,

Silber²,

Correa³

et al. 2014

ChemPhysChem

View full text Add to dashboard Cite

The behavior of water entrapped in reverse micelles (RMs) formed by two catanionic ionic liquid-like surfactants, benzyl-n-hexadecyldimethylammonium 1,4-bis-2-ethylhexylsulfosuccinate (AOT-BHD) and cetyltrimethylammonium 1,4-bis-2-ethylhexylsulfosuccinate (AOT-CTA), was investigated by using dynamic (DLS) and static (SLS) light scattering, FTIR, and (1)H NMR spectroscopy techniques. To the best of our knowledge, this is the first report in which AOT-CTA has been used to create RMs and encapsulate water. DLS and SLS results revealed the formation of RMs in benzene and the interaction of water with the RM interface. From FTIR and (1)H NMR spectroscopy data, a difference in the magnitude of the water-catanionic surfactant interaction at the interface is observed. For the AOT-BHD RMs, a strong water-surfactant interaction can be invoked whereas for AOT-CTA this interaction seems to be weaker. Consequently, more water molecules interact with the interface in AOT-BHD RMs with a completely disrupted hydrogen-bond network, than in AOT-CTA RMs in which the water structure is partially preserved. We suggest that the benzyl group present in the BHD(+) moiety in AOT-BHD is responsible for the behavior of the catanionic interface in comparison with the interface created in AOT-CTA. These results show that a simple change in the cationic component in the catanionic surfactant promotes remarkable changes in the RMs interface with interesting consequences, in particular when using the systems as nanoreactors.

show abstract

FT-IR Investigation of the Urea State in AOT Reversed Micelles

Cited by 39 publications

References 37 publications

Physicochemical investigation of acrylamide solubilization in sodium bis(2-ethylhexyl)sulfosuccinate and lecithin reversed micelles

Physicochemical investigation of acrylamide solubilization in sodium bis(2-ethylhexyl)sulfosuccinate and lecithin reversed micelles

Effect of the Constrained Environment on the Interactions between the Surfactant and Different Polar Solvents Encapsulated within AOT Reverse Micelles

Effect of the Cationic Surfactant Moiety on the Structure of Water Entrapped in Two Catanionic Reverse Micelles Created from Ionic Liquid‐Like Surfactants

Contact Info

Product

Resources

About