Effect of ethylene glycol on the special counterion binding and microstructures of sodium dioctylsulfosuccinate micelles

Extractant mediated nano-aggregate formation in Triton X-114 aided cloud formation: structural insights from TEM and SANS studies

Nanoaggregate formation by self assembly was noticed during the cloud formation of Triton X-114 in the presence of dibenzoylmethane (DBM), thenoyltrifluoroacetone (HTTA) and 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) and tributyl phosphate (TBP).

Micellization behavior of Aerosol OT in alcohol/water systems

This paper examines the effects of solvent composition on the micellization behavior of the surfactant Aerosol OT (AOT). The critical micelle concentrations of AOT in the pure solvents methanol, ethanol, propanol, and isopropanol were measured using conductiometric techniques. These solvents were then mixed with water to create solvent spectra from pure alcohol to pure water in 12 increments. Critical micelle concentrations were measured at each solvent composition. Dynamic light scattering was used to verify the presence or absence of micelles in the solvent mixtures. It was found that inverse micelles exist over a range of solvent compositions where εeff < 48 with CMCs increasing with increasing solvent polarity. Micellization was found not to occur when 48 < εeff < 80. Regular micelles formed in pure water, with the measured CMC agreeing with the literature value of 2.25 mM.

Micellization and related behavior of sodium dodecylsulfate in mixed binary solvent media of tetrahydrofuran (Tf) and formamide (Fa) with water: a detailed physicochemical investigation

The detailed aggregation behavior of sodiumdodecyl sulfate (SDS) in tetrahydrofuran (Tf)-water (W) and formamide (Fa)-water (W) media at varied volume percent compositions has been investigated. Surface tension (ST), conductance (Cond), viscosity (Visc), isothermal titration calorimetry (ITC), nuclear magnetic resonance (NMR) and small angle neutron scattering (SANS) were used in this study. The presence of nonaqueous solvents affected the critical micelle concentration (CMC) of SDS, the counter-ion binding of the micelle, the energetics of the air/water interfacial adsorption and micellization of the amphiphiles in the bulk, the ion-association (ion-pair, triple-ion, quadruple, etc. between Na(+) and DS(-) ions) as well as the weakly soluble (aggregation less) amphiphile solution. Tf has been observed to produce a "dead zone" or "non-micelle formation zone" in the mixed Tf-W domain of 10-40 vol%. Fa influenced the SDS aggregation up to 70 vol%, at higher proportions (below the Krafft temperature (K(T))), instead of the micelle, "randomly arranged globular assembly" (RAGA) was formed. The correlation of the standard free energy of micellization (ΔG(m)(0)) with different solvent parameters (1) dielectric constant (ε), (2) viscosity (η0), (3) Reichardt parameter (E(T)(30)), (4) Gordon parameter (G), and (5) Hansen-Hildebrand hydrogen bonding parameter (δ(h)) has been attempted. It has been found that δ(h) produced a master correlation between ΔG(m)(0) and δ(h) for different binary mixtures such as Tf-W, Fa-W, Ml-W and Dn-W.