Micellisation Processes in Concentrated Sodium Deoxycholate Solutions – Effect of Different Counterions

Abstract

The effect of different electrolytes (NaBr, CsBr, Bu4NBr) on the micellisation processes of Sodium Deoxycholate solutions has been studied by means of various experimental techniques (densimetric, viscometric and microwave dielectric measurements) in the concentration range above the first critical micelle concentration. The size and shape of the secondary micelles are estimated and the role of the interfacial water in these aggregation processes discussed.

Effect of sodium salicylate, sodium oxalate, and sodium chloride on the micellization and adsorption of sodium deoxycholate in aqueous solutions

“…In the presence of these sodium salts of fatty acids, cmc values of NaDC were, however, not reported [2]. Sesta et al [3] measured density, viscosity, and microwave dielectric constant of NaDC in the postmicellar concentration region in the presence of sodium bromide, cesium bromide, and tetrabutylammonium bromide, and reported only the effect of these salts on the second cmc of NaDC. Jana and Moulik [4] reported the interaction of dodecyl sulfate anion with anions of different bile salts based on surface tension, conductance, and calorimetric measurements.…”

“…Nevertheless, coions from the added electrolyte, if they have sufficient hydrophobicity in their structure, may also influence the adsorption and aggregation of ionic surfactants. In the case of bile salts, the effect of NaCl on their micellization has been studied extensively and regarding the effect of other electrolytes we could find only three reports [2][3][4]. Shilnikov et al [2] made density, ultrasound velocity, and NMR studies of sodium deoxycholate (NaDC) in the presence of sodium salts of homologous fatty acids (C 3 -C 18 ), which indicated that carboxylate ions of chain length 6C 9 do not interact with deoxycholate micelles, while those of chain length >C 9 formed mixed micelles with NaDC.…”

Supra-molecular Association and Polymorphic Behaviour In Systems Containing Bile Acid Salts

“…Micelle growth in BS is documented by a lot of experimental evidence, based on viscosity [60-64], DLS and QELS [65][66][67][68][69], NMR self-diffusion [70,71] and so forth [72][73][74]. Such data point out to the existence of an almost continuous association process, driven by surfactant uptake onto micelles and/or by the screening of the electrostatic repulsions occurring between them.…”

Micellar crowding and branching in a versatile catanionic system

“…We estimated it by the densities reported in literature, namely, 1.3 for STDC [11,12] and 1.1 for DDAB [13]. In Fig.…”

“…with D w0 the self-diffusion coefficient of free water, here approximated by the one of pure water, and ˚surf the surfactant volume fraction. We estimated it by the densities reported in literature, namely, 1.3 for STDC [11,12] and 1.1 for DDAB [13]. In Fig.…”