Small angle X-ray scattering study of an extremely elongated micelle system of CTAB-p-toluidine solution

Abstract

When p-toluidine is added to an aqueous solution of CTAB, a remarkable increase of viscosity is accompanied by a spectacular elasticity. We detected the existence of extremely elongated rod-like micelles in electron micrographs. SAXS measurements indicate a closely packed array of cylindrical rod-like micelles, brought about when solutions flow through a thin capillary. A scattering maximum of d = 160A almost corresponds to the distance between the nearest neighbours of the cylindrical rod-like micelles. This value agrees with the diameter measured on electron micrographs. The second broad peak (d = 75_~) is assigned to a subsidiary maximum of the shape function of the cylinder with infinite length.Key words: _SAXS for cationic surfactant elongated micelle, cationic surfactant _additive systems, cationic surfactant viscoelastic solution, enormously elongated rod-like micelle, hexagonally arrayed elongated cationic surfactant micelle.

Effects of KBr and n-decanol on the properties of cetyltrimethylammonium bromide micelles in aqueous solutions: A microelectrode voltammetric study

“…The physical properties of ionic micelles, especially size and shape, are dependent on the nature of the associated counter-ions [20][21][22]. Using a variety of techniques, several authors have studied the sphere-to-rod transition in micelles of cationic surfactants in aqueous solutions [7,[20][21][22][23][24].…”

Ion mobility and clustering of sodium hydroxybenzoates in aqueous solutions: a molecular dynamics simulation study

“…Even though this feature has been observed in a number of systems containing nonionic and anionic surfactants, the effect is more pronounced in cationic surfactants, especially in the presence of strongly binding counterions, which usually possess an aromatic ring. [1][2][3][4][5] Among many other systems the origin of the sphere-to-rod transition in cationic micelles with aromatic counterions has been investigated also for cetyltrimethylammonium bromide (CTAB) [6][7][8] and dodecyltrimethylammonium bromide (DTAB). 9 The experimental observations were ascribed to the specific ion hydration in the interfacial region, 7 which was indicated recently also by molecular dynamics simulations.…”

Branched Threadlike Micelles in an Aqueous Solution of a Trimeric Surfactant

“…Elongated micelles come in a wide variety of forms: from short rigid rods to flexible "giant" micellar threads that are micrometers in length (3). Threadlike micelles usually develop from spheroidal micelles when a relevant system parameter is altered (4)(5)(6). This change of shape is well understood within the framework of existing theories (1,2).…”