Stepwise association properties of some surfactant aqueous solutions

Zimmels, Y.; Lin, I. J.

doi:10.1007/bf01558158

Cited by 55 publications

(24 citation statements)

References 63 publications

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“…SDS: ex MerckSchuchardt (purity greater than 90%). The critical micelle concentration (CMC) at 23 _ I°C, measured by the conductivity method (19,20), was 7.8 x 10 -3 M, agreeing with literature data (21). CTAB: ex Fluka A.G. (purity 98.5%).…”

Section: Methodssupporting

confidence: 88%

The influence of surface-active agents on kaolinite

Welzen

Stein

Stevels

et al. 1981

Journal of Colloid and Interface Science

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The influence of surfactants (CTAB and SDS) on suspensions of monoionic kaolinite (Na ÷ and H ÷ form) was investigated by adsorption, sedimentation, turbidity, electroosmosis, and rheological measurements, at pH = 3.3 and 10.0. Only small differences are found between the Na + and H + forms of the kaolinite. The data can be accounted for satisfactorily by a mathematical model based on the DLVO theory for face-face, edge-edge, and edge-face interactions, if some assumptions on the local qJ8 potentials near edge and face type surfaces are introduced.

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Section: Methodssupporting

confidence: 88%

The influence of surface-active agents on kaolinite

Welzen

Stein

Stevels

et al. 1981

Journal of Colloid and Interface Science

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“…The presence of two cmcs indicates a two-step aggregation mechanism. Surfactants with at least two cmcs are known as ''multiple-cmc systems'' [26] and have previously been reported elsewhere [20,25,[27][28][29]. Both steps of the micellization processes in the DPC/SDS mixed micelles are endothermic (DH mic = -DH demic ) at low temperatures, and due to proximity of both cmc values, the separation of two reaction enthalpies is difficult (Fig.…”

Section: Itc Resultsmentioning

confidence: 98%

Thermodynamics, size, and dynamics of zwitterionic dodecylphosphocholine and anionic sodium dodecyl sulfate mixed micelles

Sikorska

Wyrzykowski

Szutkowski

et al. 2015

J Therm Anal Calorim

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The thermodynamic properties of micellization for dodecylphosphocholine (DPC), sodium dodecyl sulfate (SDS), and their mixtures were studied using isothermal titration calorimetry. NMR relaxation measurements were used to explore molecular mobility of the DPC-containing micelles, whereas the diffusion measurements were taken to determine the micelle size. The DPC/SDS mixed systems reveal a tendency to form two kinds of micelles in buffered solution at lower temperatures. An increase in temperature as well as the transfer of the DPC/SDS mixed micelles from buffered to unbuffered solution results in only a single-step micellization process. The average size of the DPC-containing micelles is only slightly dependent on the SDS fraction. Examination of the data of spin-spin relaxation (T 2 ) shows that methylene protons on the polar headgroup of DPC and methylene protons (H1) on the hydrocarbon chain in the micellar systems studied reveal a heterogeneous dynamic behavior reflected in a twocomponent T 2 relaxation in the whole temperature range. The latter is the main constituent of the rigid interfacial layer core protecting the penetration of water into the hydrophobic interior.

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“…If one wishes to account for thermodynamic activity coefficients to the first order, the Debye-Hückel theory can be used, but it was not used here. The mass balances for monomers and counterions are c 1 + nc n = c t , [5] c M + + nβc n = c t + c s , [6] where c t is the total surfactant concentration and c s is the concentration of added electrolyte with a common ion M + . The proportion of surfactant in dispersed particles is ignored in this model.…”

Section: Sodium Activity Resultsmentioning

confidence: 99%

“…The critical micelle concentration (cmc), normally defined as the concentration below which the solution contains negligible amounts of micelles and above which practically all additional surfactant molecules form micelles, has been reported (4)(5)(6). At the cmc, several concentrationdependent properties, such as surface tension and conductivity, undergo abrupt slope changes or exhibit "break points" due to the sudden onset of molecular aggregation (micellization).…”

Section: Introductionmentioning

confidence: 99%