Conformational state of surfactants in the solid state and in micellar form. A laser-excited Raman scattering study

Journal Article · Thu Jun 17 04:00:00 EDT 1976 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100554a015· OSTI ID:7355049

Kalyanasundaram, K; Thomas, J K

The Raman spectra of a series of cationic, anionic, and nonionic surfactants have been examined as pure solids or liquids, and in aqueous micellar solutions. The spectra show that cationic surfactants such as hexadecyltrimethylammonium bromide (CTAB), dodecylammonium chloride (DAC), and decyltrimethylammonium bromide (DeTAB), along with anionic surfactants such as sodium laurate (NaL) and sodium lauryl sulfate (NaLS) exist in all-trans structures in the crystalline state. Aqueous micellar solution of these surfactants show additional Raman lines which correspond to a liquidlike nature of the micellar core. Raman spectral studies indicate that the ethylene oxide chains in nonionic surfactant such as Igepal CO-880 and Brij 35 assume dihedral helical structures. Nonionic liquid surfactants with shorter ethylene oxide chains such as Triton X-100 and Igepal CO-630 have a major part of the ethylene oxide chain in an open coil form. No significant differences are observed in Brij 35 in H/sub 2/O. However, micellization of Igepal CO-630 shows spectra which indicate a partial ordering of the ethylene oxide chains. The phase changes associated with the electrolyte-induced sphere-rod transition in micellar systems have also been examined by Raman spectroscopy. These studies show a greater ordering of the hydrocarbon chain in the rod-shaped compared to the sphere-shaped aggregates.

• Research Organization: Univ. of Notre Dame, IN
• OSTI ID: 7355049
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 80:13; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400104 -- Spectral Procedures-- (-1987)
400500* -- Photochemistry
ELECTROMAGNETIC RADIATION
LASER RADIATION
MICELLAR SYSTEMS
RADIATIONS
RAMAN SPECTRA
SOLIDS
SPECTRA
SURFACTANTS