Surface and Bulk Properties of Dodecylbenzenesulphonate in Aqueous Medium: Role of the Nature of Counterions

Abstract

The lithium, potassium, and ammonium salts of dodecylbenzenesulphonic acid have been prepared from the pure sodium salt by applying ion-exchange technique. The critical micellization concentrations (CMC) of the surfactants with four different counterions have been determined in a temperature range of 10 C to 40 C using surface tension as well as electrical conductivity measurements. The counterion ionization constant, a, and various thermodynamic parameters of micellization viz, DG 0 m , DH 0 m , DS 0 m , D mic C 0 p along with the surface parameters (C max , A min ) in aqueous media have been determined. The CMC value of dodecylbenzenesulphonate (DBS) having different counterions followed the order Na þ > Li þ > NH þ 4 > K þ . While large negative free energy change ðDG 0 m Þ and the positive entropy change ðDS 0 m Þ favor the micellization process thermodynamically, nature of their variation with counterion supports the importance of hydrated counterion size factor in micellization process via a change in the hydrophilicity of surfactant head group along with the structure of branched chain of hydrocarbon tail.

Amphiphilic Properties of Dodecylammonium Chloride/4‐(1‐Pentylheptyl) Benzene Sodium Sulfonate Aqueous Mixtures and Study of the Catanionic Complex

“…As previously mentioned, the elemental analysis revealed the formation of the catanionic molecular complex DA-DBS, C 12 The process took place at high concentrations of the surfactants (Fig. 2, point D), where vesicle breakage occurred and the less soluble catanionic salt, DA-DBS ( Fig.…”

“…In general with the headgroup moves from the end to the center of the dodecyl chain, the hydrophobicity, Krafft temperature, as well as surface tension monotonically decrease [10], but the critical aggregation concentrations and the minimum area per molecule increase [9]. Approximately linear relationships exist between headgroup position along dodecyl chain and log critical aggregation or micellization concentrations, minimum area per molecule at the air-aqueous solution interface, standard free energy of micellization, and maximum surface excess [9,11,12]. Obviously in the mixture with cationic surfactants, the exact molecular structure of LAS strongly influences not only the effective molecular shape or ability to self-assemble into aggregate, but also the aggregate packing constraints in catanionic complexes.…”

Tuning of physico-chemical characteristics of charged micelles by controlling head group interactions via hydrophobically and sterically modified counter ions

“…All the surfactants with inorganic and organic counterions were prepared by the ion exchange technique starting from sodiumdodecylbenzene sulfonate following the procedure as mentioned below. 17,18,21 A solution of sodiumdodecylbenzene sulfonate in 1 : 1 (v/v) mixture of water and ethanol was prepared. The surfactant solution was then passed through an ion-exchange column (dimension of 40 cm by 2 sq.…”

“…Although the effect of the nature of counter ions of anionic surfactants is less signicant than that of cationic surfactants, hydrophobic counter ions can bring about relatively stronger modication in the aggregation behaviour. Therefore a considerable number of literatures have been found 2,14,15,18,21 concerning micellar growth as affected by hydrotropic counter ions of both cationic and anionic surfactants. In this connection it may be anticipated that symmetrical organic counter ions might interact with the surfactant head groups more effectively via strong hydrophobic interaction with the terminal hydrocarbons of surfactant molecule.…”

Effect of Template Type on theTrametes versicolorLaccase-Catalyzed Oligomerization of the Aniline Dimerp-Aminodiphenylamine (PADPA)

“…14,67 On the other hand, SDBS in the same aqueous solution forms micelles at a critical concentration for micelle formation (cmc) that may be different from the cvc of AOT vesicles; vesicles and micelles are different types of polymolecular assemblies. Literature values for the cmc value of SDBS (a complex mixture of isomers) 13,62,63 at 25 °C in water are 3.1, 68 2.7–2.9, 62 1.4–1.9, 69,70 or 1.2 mM. 71 Although the values deviate, possibly due to the different sources of SDBS and the method of cmc determination, the cmc value for SDBS in the pH 3.5 solution used (0.1 M NaH 2 PO 4 ) is expected to be lower than the cmc value determined in deionized water; 72 see Section 3.…”