A Raman investigation of a nonionic surfactant (C12E8)-water system: comparison with the C8E5-water system

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

“…More significant conformational changes are observed within the region of the particular phases. The previous authors 26,28 have shown that there are some spectral changes with temperature in the L 1 phase and interpreted them to be associated with the conformational change of the hydrophilic oxyethylene moiety. The conformation of C 12 E 5 in water and in the neat liquid has been studied by 13 C NMR spectroscopy.…”

“…Molecular conformation in other C n E m -water systems has been studied by Raman spectroscopy. Gaufre `s and co-workers 26,28 have shown using a difference spectrum technique that there is no significant spectral changes at the transition between the isotropic micellar solution (L 1 ) phase and the hexagonal (H 1 ) phase in the C 8 E 5 -water system 26 and at the transition between the L 1 phase and the cubic (I 1 ) phase in the C 12 E 8 -water system. 28 They concluded therefore that there is no discontinuity in the conformational state of the molecular chain at these phase transitions.…”

“…Gaufre `s and co-workers 26,28 have shown using a difference spectrum technique that there is no significant spectral changes at the transition between the isotropic micellar solution (L 1 ) phase and the hexagonal (H 1 ) phase in the C 8 E 5 -water system 26 and at the transition between the L 1 phase and the cubic (I 1 ) phase in the C 12 E 8 -water system. 28 They concluded therefore that there is no discontinuity in the conformational state of the molecular chain at these phase transitions. This conclusion is consistent, although they were looking at unresolved overall conformational state of the molecular chain, with our present results for the C 12 E 3 -water system that the conformational change of the dodecyl chain at the L 2 /L R phase transition is not significant.…”

“…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…”

“…[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.…”