Tetraalkylammonium ion induced micelle-to-vesicle transition in aqueous sodium dioctylsulfosuccinate solutions

The effect of hydrotropic organic coions on the physicochemical behavior of ionic surfactants has not yet been understood clearly, although as counterions they are known to have a remarkable effect on the microstructures of ionic surfactants. In this paper therefore the aggregation behavior of sodium dioctylsulfosuccinate (AOT) has been studied in aqueous media in the presence of sodium benzoate (NaB)/ sodium salicylate (NaSa)/sodium meta-hydroxybenzoate (Na-mHB)/sodium para-hydroxybenzoate (NapHB). Surface tension and small angle neutron scattering (SANS) techniques are mainly used. AOT is known to have a special counterion binding behavior (SCB) with respect to sodium counterion, viz., at about 0.015 mol kg À1 of added NaCl the counterion binding constant of AOT increases suddenly by two fold which is attributed to the shape change of the AOT micelle. The SCB of AOT is found to exist in the presence of benzoate, m-hydroxybenzoate and p-hydroxybenzoate coions, but not in the presence of o-hydroxybenzoate (salicylate) coions. The SANS data, on the other hand, showed that shape transition of the AOT aggregate takes place in the presence of all the four hydrotropic coions; the concentration of NaSa required to induce the shape transition was however higher. A sharp increase in the value of the hydrodynamic diameter determined by the dynamic light scattering (DLS) experiments also indicates the shape transition of AOT aggregates in the presence of the salts. Chemical shift values of benzoate and hydroxybenzoates confirmed the binding of these coions to an AOT micelle. The binding of the salicylate coion is shown to be stronger due to its low hydration energy and high pK h (K h is the hydrolysis constant) values.

show abstract

“…47,50 In this method of data analysis, the differential scattering cross section per unit volume (dS/dU) is given by the expression…”

Section: Methodsmentioning

confidence: 99%

“…The different equations used in the determination of the shape of aggregates are given elsewhere. 47,50 AOT + NaB + D 2 O system. The SANS data for the 15 mM AOT solution with varying concentration (10-70 mM) of the added NaB are shown in Fig.…”

Section: Sans Measurementsmentioning

confidence: 99%

Influence of hydrotropic coions on the shape transitions of sodium dioctylsulfosuccinate aggregates in an aqueous medium

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…AOT micelles have unusually big size as compared to other ionic surfactants. This could be due to the extensive hydration of the head group, which has been discussed in one of our previous works …”

Section: Resultsmentioning

confidence: 76%

AOT Micelles/Vesicles for Synthesis of Silver Nanoparticles and Micellar Transitions Affected by Nanoparticles

et al. 2016

View full text Add to dashboard Cite

A facile method for the synthesis of silver nanoparticles (Ag NPs) is reported using sodium para‐toluene sulphonate (NaPTS) as the reducing agent and AOT micelles and vesicles as capping agents, leading to the development of a system comprising of AOT micelles/vesicles along with Ag NPs. A single component, Na‐PTS, has been used to tune the micellar aggregates as well as for the synthesis of Ag NPs. The aggregation behavior of AOT in aqueous Na‐PTS has been studied by the method of surface tension and the changes in the morphology of AOT micelles by small angle neutron scattering (SANS) measurements. The synthesis of Ag NPs have also been carried out using common reducing agents such as sodium borohydride and ascorbic acid. SANS measurements have also been performed in the ternary systems of micelles, vesicles and NPs and reveal the formation of fractal structures of the NPs. The ternary systems have been also tested for their antibacterial activity. A very important observation made in the present study is the large decrease in the concentration of salt required to bring about micellar shape transition in the presence of small amounts of NPs.

show abstract

“…From the pioneering studies by Kaler on oppositely charged single tailed surfactants [29][30][31][32][33][34] numerous contributions have been reported on the spontaneous vesicle formation and micelle-vesicle transitions produced as a function of the surfactant ratio in the mixture [35][36][37][38][39][40][41]. Similar vesicle formation should be expected when a cationic surfactant is mixed with an ionic liquid displaying anionic surfactant-like behavior.…”

Section: Introductionmentioning

confidence: 70%

Catanionic surfactant formation from the interaction of the cationic surfactant hexadecyltrimethylammonium bromide (CTAB) and the ionic liquid 1-butyl-3-methylimidazolium octyl sulfate (bmim-octyl SO4) in aqueous solution

Comelles

Ribosa

González

et al. 2015

Colloids and Surfaces A: Physicochemical and Engineering Aspect

View full text Add to dashboard Cite

The interaction between the cationic surfactant Hexadecyltrimethylammonium bromide (CTAB) and the ionic liquid 1-butyl-3-methylimidazolium octyl sulfate (bmim-octylSO 4 ) in aqueous solution has been investigated at two total concentrations (0.5 and 10 mM) and different CTAB mole fractions ( CTAB ).Samples of different physical appearance were obtained depending on  CTAB suggesting different kind of aggregates. Bluish solutions ( CTAB from 0.1 to 0.6) were assigned to vesicles of the catanionic surfactant formed (CTA-octylSO 4 ), whereas clear and isotropic solutions ( CTAB  0.6) corresponded to mixed micelles. Surface tension, electrical conductivity, absorbance and dynamic light scattering (DLS) measurements were performed with the aim of correlating properties changes with the aggregation structures. The critical aggregation concentration (cac) and the surface tension value at the cac ( cac ) were much lower for the mixtures than for the individual components. Thiis finding reveals the 3 exceptional surface activity of these mixtures, attributable to the formation of the CTA-octylSO 4 catanionic surfactant. Once the catanionic surfactant is formed it makes no sense to consider anymore the initial CTAB / bmim-octylSO 4 binary system but a new one composed by CTA-octylSO 4 and the excess of bmimoctylSO 4 or CTAB. On the basis of this consideration the surface activity parameters have been recalculated.

show abstract

Tetraalkylammonium ion induced micelle-to-vesicle transition in aqueous sodium dioctylsulfosuccinate solutions

Cited by 45 publications

References 71 publications

Influence of hydrotropic coions on the shape transitions of sodium dioctylsulfosuccinate aggregates in an aqueous medium

Influence of hydrotropic coions on the shape transitions of sodium dioctylsulfosuccinate aggregates in an aqueous medium

AOT Micelles/Vesicles for Synthesis of Silver Nanoparticles and Micellar Transitions Affected by Nanoparticles

Catanionic surfactant formation from the interaction of the cationic surfactant hexadecyltrimethylammonium bromide (CTAB) and the ionic liquid 1-butyl-3-methylimidazolium octyl sulfate (bmim-octyl SO4) in aqueous solution

Contact Info

Product

Resources

About