Amphiphile Behavior in Mixed Solvent Media I: Self-Aggregation and Ion Association of Sodium Dodecylsulfate in 1,4-Dioxane–Water and Methanol–Water Media

Abstract

Mixed aquo-organic solvents are used in chemical, industrial, and pharmaceutical processes along with amphiphilic materials. Their fundamental studies with reference to bulk and interfacial phenomena are thus considered to be important, but such detailed studies are limited. In this work, the interfacial adsorption of sodium dodecylsulfate (SDS, C12H25SO4(-)Na(+)) in dioxane-water (Dn-W) and methanol-water (Ml-W) media in extensive mixing ratios along with its bulk behavior have been investigated. The solvent-composition-dependent properties have been identified, and their quantifications have been attempted. The SDS micellization has been assessed in terms of different solvent parameters, and the possible formation of an ion pair and triple ion of the colloidal electrolyte, C12H25SO4(-)Na(+) in the Dn-W medium has been correlated and quantified. In the Ml-W medium at a high volume percent of Ml, the SDS amphiphile formed special associated species instead of ion association. The formation of self-assembly and the energetics of SDS in the mixed solvent media have been determined and assessed using conductometry, calorimetry, tensiometry, viscometry, NMR, and DLS methods. The detailed study undertaken herein with respect to the behavior of SDS in the mixed aquo-organic solvent media (Dn-W and Ml-W) is a new kind of endeavor.

Nonclassical Hydrophobic Effect in Micellization: Molecular Arrangement of Non‐Amphiphilic Structures

“…[1,2] The micellization of low-molecular weight surfactants is a thermodynamic process where the water structure around hydrophobic parts of the molecules plays a significant role. [1,[4][5][6][7][8] The driving force of micellization is related to the classical hydrophobic effect, based on the cohesive energy of water around hydrophobes, and where enthalpy and entropy contributions to water structuring compensate each other. [9] This is counterbalanced by electrostatic repulsion or interfacial tension, resulting in micelles with low dispersity in aggregation number.…”

The Effect of Polar Head and Chain Length on the Physicochemical Properties of Micellization and Adsorption of Amino Alcohol‐Based Surfactants

“…The aggregation of surfactants in micellar structures is a phenomenon that depends on the molecular structure of the surfactant and the conditions of the surfactant solution (Akram et al, ; Grillo et al, ; Lv et al, ; Pan et al, ; Phani Kumar et al, , ; Prameela et al, , , ; Wattebled and Laschewsky, ). The formation of micelles for ionic surfactants in solution is mainly controlled by the equilibrium between two opposing forces such as the attractive interaction between the linear hydrophobic chains and the electrostatic repulsion between the ionic groups (Akram et al, ; Maiti et al, ).…”

Molecular Level Insights on Collagen–Polyphenols Interaction Using Spin–Relaxation and Saturation Transfer Difference NMR

“…[9][10][11][12][13][14] It is well known that NMR chemical shit (δ) is sensitive to changes in electronic environment, 11,12 whereas spin-lattice relaxation time (T 1 ) and spin-spin relaxation time (T 2 ) data provide rich information on fast and slow dynamics, respectively. [15][16][17][18] Furthermore, through selective T 1 measurements and their data analysis, the binding affinities of ligands with protein [19][20][21][22] can be estimated in a straightforward manner. In this connection, the determination of all the NMR parameters, namely, the chemical shift (δ), non-selective and selective spin-lattice relaxation times (T 1NS and T 1SEL ) and spin-spin relaxation times (T 2 ) of the ligand in the presence of protein would be beneficial to glean further insights about ligand binding and dynamics.…”