Phase transition in non-ionic surfactant—water systems as studied by Raman spectrometry

Bribes, Jean-Luc; Gaufrès, Robert; Sportouch, Serge; Maillols, Jacques

doi:10.1016/0022-2860(86)80298-8

Cited by 6 publications

(4 citation statements)

References 5 publications

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“…By using these marker bands, detailed conformational analysis is possible even for complex systems. We have studied by Raman spectroscopy the molecular conformation of a series of C n E m surfactants ( n = 1−16 and m = 1−8) in the solid state and have clarified the relation between the conformation and the chain length. − Vibrational spectroscopy has been applied extensively to aqueous solutions of C n E m and other related surfactants. − In most of these studies, the molecular structure has been discussed in relation to the phase transitions in the surfactant−water systems. The phase and conformational transitions in lipids and biomembranes have also been studied by vibrational spectroscopy…”

Section: Introductionmentioning

confidence: 99%

“…[18][19][20][21] Vibrational spectroscopy has been applied extensively to aqueous solutions of C n E m and other related surfactants. [22][23][24][25][26][27][28][29][30][31][32][33][34] In most of these studies, the molecular structure has been discussed in relation to the phase transitions in the surfactant-water systems. The phase and conformational transitions in lipids and biomembranes have also been studied by vibrational spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Conformational Analysis of Nonionic Surfactants in Water by a Selective Monodeuteration Method. C−D Stretching Infrared Spectroscopy of α-Monodeuterododecyl-ω-hydroxytris(oxyethylene)s

1996

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The conformation of the alkyl chain in α-dodecyl-ω-hydroxytris(oxyethylene) (C12E3) in water has been studied by C−D stretching infrared spectroscopy. This conformational analysis is based on the fact that the wavenumbers of the isolated C−D stretching vibrations are sensitive to the conformation in the vicinity of the C−D bond. Infrared spectra were measured for five selectively monodeuterated species of C12E3, namely CH3(CH2)11-k CHD(CH2) k -1(OCH2CH2)3OH, where k = 1, 2, 4, 6, and 8, in the lamellar (Lα) and isotropic solution (L2) phases. The C−D stretching bands for each of the monodeuterated species were assigned to particular conformations of the specifically deuterated part of the chain. From the observed intensities of the C−D stretching bands, the fractions of the trans conformation around the dodecyl C−C bonds and the oxyethylene-adjoining O−C bond and the fractions of the consecutive trans conformations around the two adjoining bonds were evaluated. The conformational change at the phase transition from L2 to Lα is not significant and only a small increase in the trans fraction is observed for the C−C bonds close to the alkyl/oxyethylene interface. This implies that the conformational states in the L2 and Lα phases in the vicinity of their boundary are substantially not different. In the Lα phase, when the composition or the temperature approaches the region of the phase separation or transition, the trans fractions for the C−C bonds closer to the alkyl/oxyethylene interface and those closer to the chain terminal decrease significantly. These observations indicate that the conformational transformation from trans to gauche at these chain positions makes the lamellar structure less stable and leads eventually to the structural destruction. The fraction of the consecutive trans conformations may be used as a measure of the conformational order at particular positions of the chain. The present results show that the ordering is the highest in the middle of the chain in the Lα and L2 phases. This vibrational spectroscopic observation, together with the previous NMR observations, indicates that the alkyl/oxyethylene interface is flexible with respect to the conformation and the orientation of the chain.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Conformational Analysis of Nonionic Surfactants in Water by a Selective Monodeuteration Method. C−D Stretching Infrared Spectroscopy of α-Monodeuterododecyl-ω-hydroxytris(oxyethylene)s

1996

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“…Conformational changes in this work are primarily quantified by analyzing the ratio of trans to gauche conformations in the hydrocarbon chain. Raman spectroscopy is particularly suited to studying the hydrocarbon chain and has been applied to surfactant and lipid systems by a variety of authors. − In n -alkanes with up to 18 carbon atoms, the all- trans configuration has been shown to be the most stable . While the gauche conformation is less energetically favorable for hydrocarbon chains, they are present in solution because small amounts of energy are sufficient to overcome the energy barrier between trans and gauche conformations.…”

Section: Introductionmentioning

confidence: 99%

“… 16 While the gauche conformation is less energetically favorable for hydrocarbon chains, they are present in solution because small amounts of energy are sufficient to overcome the energy barrier between trans and gauche conformations. It has been shown that the abundance of gauche and trans segments can abruptly change as a result of a phase transition, 2 , 13 , 17 as the trans conformation becomes more energetically favorable at higher concentrations, where the energy barriers are harder to overcome. One drawback of Raman spectroscopy is that, while specific spectra peaks can be assigned to various conformations, the exact relationship between a peak’s magnitude and the abundance of said conformation in solution is unknown.…”

Section: Introductionmentioning

confidence: 99%

Using Raman Spectroscopy and Molecular Dynamics to Study Conformation Changes of Sodium Lauryl Ether Sulfate Molecules

et al. 2023

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A study using both Raman spectroscopy and molecular dynamics (MD) simulations was carried out for alkyl ethoxysulfate (AES) surfactants at various concentrations in solution. Direct comparison between experiment and simulation shows that the conformational changes observed in MD are in good agreement with those obtained via Raman spectroscopy. We show that there is an increase in the relative number of trans conformations with increasing concentration and illustrate the relationship between phase structure and molecular conformation, which is often speculated but difficult to confirm. Our results open up the possibility of applying MD to other surfactants, with the aim of analyzing conformational behavior, which can typically be difficult to study experimentally using spectroscopy methods, due to large numbers of vibrational modes present in large complex molecules.

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Phase transitions in non‐ionic surfactant–water systems as studied by Raman spectrometry. II—A new methodology

Gaufrès

Bribes

Sportouch

et al. 1988

J Raman Spectroscopy

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In order to compare the molecular Raman spectra between an optically isotropic phase and an anisotropic phase, a method is proposed having especially in view the study of transitions in lyotropic surfactant systems. Its application to the transition between the isotropic and hexagonal phases in the water-a-octyl-w-hydroxypentakis (oxyethylene) system shows that there is no significant molecular structure change at transition. This result suggests that all the micelles in the L, phase in equilibrium with the hexagonal phase have a cylindrical shape.

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Phase transition in non-ionic surfactant—water systems as studied by Raman spectrometry

Cited by 6 publications

References 5 publications

Conformational Analysis of Nonionic Surfactants in Water by a Selective Monodeuteration Method. C−D Stretching Infrared Spectroscopy of α-Monodeuterododecyl-ω-hydroxytris(oxyethylene)s

Conformational Analysis of Nonionic Surfactants in Water by a Selective Monodeuteration Method. C−D Stretching Infrared Spectroscopy of α-Monodeuterododecyl-ω-hydroxytris(oxyethylene)s

Using Raman Spectroscopy and Molecular Dynamics to Study Conformation Changes of Sodium Lauryl Ether Sulfate Molecules

Phase transitions in non‐ionic surfactant–water systems as studied by Raman spectrometry. II—A new methodology

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