Unusual volumetric and hydration behavior of the catanionic system sodium undecenoate: sodecyltrimethylammonium bromide

Effect of Double Bonds in the Formation of Sodium Dodecanoate and Sodium 10-Undecenoate Mixed Micelles in Water

“…This last surfactant was chosen because it was extensively studied in this laboratory. [2][3][4]7,8 Theory…”

Computational Study of the Structure and Behavior of Aqueous Mixed System Sodium Unsaturated Carboxylate-dodecyltrimethylammonium Bromide

“…It can be seen that there is a certain correlation between the experimental partial molar volumes and the water excluded volumes. Since the partial molar volume is not the true volume of the solute molecules, it is not expected that both properties be equal (except for ideal mixtures, which is not the case in the studied system 4 ), but the general trends must be the same.…”

“…19 The presence of the double bond in the SUD molecule produces an unusual nonideality in the partial molar volume behavior of the mixed SUD-DTAB micelles, and the phenomenon was explained on the basis of the energy of interaction between the π-electrons of the double bond and water. 4 The difference in polymerization yields of SUD mesophases when initiated by water soluble initiators (34.5% in hexagonal mesophase, 19% in lamellar liquid crystal 20 ) and by γ-irradiation (83% in hexagonal and 60 in lamellar 21 ) was explained on the basis of the vinyl groups exposed to the initiator: the water soluble initiator can only promote the polymerization of the double bonds exposed to water, while the γ-radiation can also initiate the polymerization of the double bonds inside the liquid crystal structure. 21 Unpublished results on SUD-sodium dodecanoate (SDD) mixed micelles indicate that there is a preferential proportion of about 0.36-0.4 mol fraction of SUD in micelles, and the interaction is strongly attractive, with an interaction parameter of β M ) -4.22 k B T, while the value must be zero if the interactions were ideal.…”

“…The formation of the coacervate was also studied and explained on the basis of the packing parameter computed by that of DTAB and that of a SUD molecule folded to expose the vinyl group to water, which gives a curvature that impedes the formation of planar structures even when the ζ-potential at the surface of aggregates approaches zero . The presence of the double bond in the SUD molecule produces an unusual nonideality in the partial molar volume behavior of the mixed SUD-DTAB micelles, and the phenomenon was explained on the basis of the energy of interaction between the π-electrons of the double bond and water …”

“…Previous work in our laboratory indicated that the presence of a double bond in the alkyl chain of one component in a surfactant mixture gives rise to properties that were not contemplated in the current theories on mixed surfactant systems. [1][2][3][4] Also, the presence of the double bond in the alkyl chain and its interaction with water explains the polymerization behavior in the different microstructures (micelles, lamellar or hexagonal mesophases) of polymerizable surfactants. 5,6 The molecular mechanism that produces hydrophobicity is one of the most important that determines the thermodynamic stability of globular proteins, micelles, and biological membranes.…”