Sodium Alkyl Sulfates Research Articles

Binding of Sodium Alkyl Sulfates to Human Erythrocyte Studied with a Surfactant Ion Selective Electrode

To clarify the mechanism of the shape change of human erythrocyte induced by anionic surfactants, the binding of sodium alkyl sulfates (C n H 2n+1 OSO 3 Na, n = 8, 10, 12) to human erythrocyte was studied. In the binding experiments with surfactant ion selective electrodes, it was found that all surfactants studied bound to the erythrocyte in two steps in the concentration range where the shape change occured. From the analysis of binding isotherms, the binding constants (K 1 , K 2 ) and the total number of sites (n 1 , n 2 ) for number of the carbon atoms of the alkyl group of the surfactants. These facts suggests that the first binding is stronger than the second binding and that the hydrophobic interaction between the alkyl chain of the surfactants and the erythrocyte is the main driving force for each binding. Meanwhile, from the optical the second binding. Furthermore, to identify the binding sites on the erythrocyte membrane for the surfactants, the differential scanning calorimetry (DSC) measurements of erythrocyte ghost were done, and it was elucidated that the first binding site was the boundary lipid region of band 3 and the second binding site was the phospholipid layer of the erythrocyte membrane. These results imply that the shape change of the erythrocyte progresses via two steps of surfactant binding, first, to the membrane protein, band 3, and second, to the lipid layer of the erythrocyte, and that the membrane proteins also play an important role in the mechanism of the shape change of the erythrocyte.

Effect of Surfactant Tail-Length Asymmetry on the Formation of Mixed Surfactant Vesicles

A fundamental understanding of vesicle formation and stability in mixed surfactant systems is important for the description of their phase behavior, for the application of vesicles as encapsulating devices, and for the elucidation of cholesterol gallstone formation in bile. With this in mind, we have utilized our recently developed molecular-thermodynamic theory to study the formation of vesicles in mixtures containing cetyltrimethylammonium bromide (CTAB) and sodium alkyl sulfates of various tail lengths. The theory accounts for the essential free-energy contributions to the free energy of vesiculation, gves, with particular emphasis on their relative importance and interplay in the process of vesicle formation. We found that mixed surfactant vesicles can be stabilized energetically in highly asymmetric surfactant mixtures, such as those consisting of CTAB and sodium pentyl sulfate (SPS). These vesicles are characterized by small sizes and a narrow size distribution. In contrast, in mixtures consisting of CTAB and sodium pentadecyl sulfate (SPDS), where the tail-length asymmetry is small, vesicles are stabilized entropically and are characterized by large sizes and a wide size distribution. Small vesicles are formed by placing more molecules in the outer vesicle leaflet to relieve the outer interfacial free-energy penalty. The SPS molecules, having a short hydrophobic tail, can cover the outer hydrocarbon/water interface without incurring a high packing free-energy penalty, thus making gves of small CTAB/SPS vesicles lower than that corresponding to a planar bilayer. In contrast, a high packing free-energy penalty is incurred in small CTAB/SPDS vesicles, due to the existence of a more crowded hydrophobic region. In this case, therefore, gves of finite-sized vesicles is always higher than that corresponding to a planar bilayer, and the formation of vesicles in such systems is driven by the more favorable entropy of mixing. Surfactant tail-length asymmetry also affects the optimum composition of the vesicles by altering the tail transfer free-energy contribution, gtr. Decreasing surfactant tail-length asymmetry reduces gtr, which, in turn, decreases the influence of the energetics of vesicle formation, as compared to that of the entropy associated with localizing the surfactant molecules. In a mixture containing CTAB and SPDS (weight ratio = 3/7), therefore, the entropic penalty dominates and drives the vesicle composition toward that of the bulk solution. In contrast, in highly asymmetric mixtures such as those consisting of CTAB and SPS (weight ratio = 3/7), the optimum vesicle composition reflects a compromise between the entropic and energetic factors. The effect of decreasing surfactant tail-length asymmetry on the optimum vesicle composition is therefore similar to that of adding salt to the vesicle solution. Specifically, decreasing tail-length asymmetry reduces the energetic influence by decreasing gtr, while adding salt produces the same effect through a reduction in the electrostatic free-energy contribution, gelec.

Growth of Sodium Dodecyl Sulfate Micelles with Detergent Concentration

Sodium alkyl sulfate micelles are predicted to grow as a power law of the total counterion salt concentration, Yaq, in the aqueous phase as follows: NA = K~(Y~~)Y, where NA is the micelle aggregation number and ~2 and y are constants which are estimated from the critical micelle concentration and the apparent degree of counterion attachment. For sodium dodecyl sulfate, NA = 162(Y,q)1/4 is predicted and is shown to be in good agreement with aggregation numbers measured by a number of techniques over a wide range of Yaq whether this quantity is varied by changing the concentrations of the detergent, the added counterion salt, or both. Values of ~2 and y are estimated for six members of the sodium alkyl sulfate family.

Dynamic surface tensions of surfactant mixtures at the water-air interface

Studies of dynamic surface tensions γ( t) using an automated maximum bubble pressure method in the time interval from 1 ms to 30 s are performed with mixtures of non-ionic surfactants (Triton X-45, X-100, X-114, X-165, X-305 and X-405) and sodium alkyl sulphates (decyl, dodecyl, tetradecyl and hexadecyl). In the range of longer times t the dependencies γ( 1 √t ) of the single components show linear behaviour, giving evidence for a diffusion controlled adsorption in the absence of disturbing amounts of surface active impurities. Similar results are obtained on the addition of a second component with a sufficiently high surface activity. The adsorbed amount calculated from the ( γ( 1 √t ) ) dependences using a modified Hansen-Joos approximate relation agree well with those obtained from equilibrium surface tension data. The experimental γ( 1 √t ) curves of some surfactant mixtures show small jumps in the range over which displacement of the lower component by the stronger surface active molecules is introduced. These surface tension jumps are used to calculate the rate constants of desorption of sodium decyl and dodecyl sulphate. The obtained value of k ad = 50 s −1 is in good agreement with earlier published data for these surfactants.

The analysis of dynamic surface tension of sodium alkyl sulphate solutions, based on asymptotic equations of adsorption kinetic theory

We analysed existing and newly derived asymptotic solutions of the adsorption kinetic equations for the liquid phase interface in the regions of infinitely small and infinitely great surface lifetimes ( t) for the cases of one and of a few surfactants, on non-deforming and deforming surfaces, under non-stationary, stationary and quasi-stationary conditions, assuming either the diffusion adsorption mechanism or mixed adsorption mechanism. It was proved that in the region t → ∞, the adsorption barrier does not influence the dynamic surface tension σ, but the role of surface-active contaminants is significant. In contrast, in the region t → 0, the role of contaminants is small, but the adsorption barrier influences the dynamic surface tension substantially. The dynamic surface tension of sodium alkyl sulphate solutions was measured by the maximum bubble pressure method, in the t range 0.001–10 s. In the region t → ∞ we obtained good agreement of experimental results with asymptotic formulae. The diffusion adsorption mechanism of the surfactant solutions studied was confirmed and we also estimated the concentration values of the surfactant admixtures. Small additions of the more active surfactant sodium tetradecyl sulphate to sodium dodecyl sulphate substantially influences the shape of the σ— t curve in the region t → ∞, increasing (in full accordance with theoretical considerations) the tangent value of the curve inclination of the dependence of σ on t −1/2. In the regions t → 0, long-chained high molecular weight sodium alkyl sulphates adsorb according to the diffusion mechanism, whereas for sodium decyl and dodecyl sulphates the existence of the adsorption barrier was confirmed. We corroborated experimentally the absence of any influence of surfactant admixtures on the values of dynamic surface tension at t → 0.

An alternative study of the skin irritant effect of an homologous series of surfactants

An attempt has been made to differentiate between in vivo and in vitro skin reactions to a homologous series of surfactants (sodium alkyl sulfate, R-OSO 3 Na) and to determine the usefulness of percutaneous absorption in vitro as an alternative test system. Sodium alkyl sulfate showed considerable biological activity by virtue of its polar head groups. The length of the lipophilic chain in the surfactants was an important factor in their overall activity. The following in vivo tests were performed: a primary skin irritation test in guinea pigs, a primary eye irritation test in rabbits and a closed patch test in humans. Peak skin irritation occurred with C 10-C 16 sodium alkyl sulfate, which had lipophilic groups of different alkyl chain lengths. Cell injury was also evaluated by the neutral red dye uptake assay in rabbit corneal (RC) cells. C 4 and C 6 compounds had no effect, while maximal effects occurred with C 18. Protein denaturation and haemolysis occurred with C 10-C 16 compounds. In the percutaneous absorption test in guinea pig skin, permeation was low for the C 18 compound and high for the C 4 compound. The results with the C 18 compound suggest that differences between cell injury and skin irritation result from skin permeation. Although the C 18 compound caused cell injury, membrane destruction and protein denaturation were more severely with the C 10-C 16 compounds, owing to their strong haemolytic and protein-denaturation action.

Dual Use of Micellar-Enhanced Ultrafiltration and Time-Resolved Laser-Induced Spectrofluorimetry for the Study of Uranyl Exchange at the Surface of Alkylsulfate Micelles

Micellar-enhanced ultrafiltration (MEUF) and time-resolved laser-induced spectrofluorometry (TRLIS) have been used to study the interaction between the uranyl ion (UO 2+ 2) and sodium alkylsulfate micelles. The studies were performed at a constant pH and various uranium concentrations. It has been found that the uranyl ion is rejected by an ultrafiltration membrane due to the ion's strong interaction with the micellar surface. The association constant of UO 2+ 2 to dodecyl and tetradecyl sulfate micelles was investigated. Assuming that adsorption in the Stern layer is described by a Langmuir isotherm, ion exchange constants were found to be significantly higher than those obtained for other divalent ions belonging to the d-block (Cu 2+, Co 2+). The influence of the surfactant chain length upon ion exchange constants of uranium has also been stressed. A limiting rejection rate has been presented and an expression has been proposed.

Inclusion complexation of sodium alkyl sulfates with?-cyclodextrin. A1H NMR study

The association of anionic surfactants,viz., sodium alkyl sulfates, C n H2n+1OSO3Na (n=5, 6, 7, 8, 9, 10, 12), withβ-cyclodextrin has been investigated by means of NMR spectroscopy. The measurements of chemical shift changes of certain protons of both host and guest molecules indicated 1:1 inclusion complex formation. The association constants (K a) and standard free energy changes (−ΔG 0) for the inclusion complexation reaction vary as a function of the hydrocarbon chain length of the surfactants.

A study of vitamin A as a probe in critical micelle concentration determinations of surfactants

The critical micelle concentrations (CMC) of some sodium alkyl sulfates (SNS, SdS, SDS, STS, and SHS), sodium dodecyl sulfonate (SDSO), CTAB and Triton X-100 were determined by measuring both the absorbance and the absorption wavelength of vitamin A in aqueous solutions of surfactants of various concentrations. The results are in agreement with those obtained by other methods in the literature. The influence of micelles upon the absorption spectra of vitamin A have been investigated. The effects of the temperature and the incubation time on the measurements have been discussed.

Hydration of the organized molecular assembly of ionic surfactants as studied by vapor pressure and x-ray diffraction

Equilibrium vapor pressure of water was measured for ionic surfactant-water binary systems as a function of water content over the temperature range 5–11°C. The measurement of x-ray powder diffraction has also been performed to characterize the microscopic structures of these two-component systems. Examined surfactants were the homologs of sodium alkyl sulfate and alkyltrimethylammonium bromide. It was found that dodecyl and decyl sulfate formed solid di-and trihydrate respectively, while octyl sulfate and the cationic surfactants formed lyotropic liquid crystal instead. The x-ray long spacing of the liquid crystals scarcely varied with water content.Enthalpy of vaporization was calculated for both solid hydrates and lyotropic liquid crystals.

Structural effect on the adsorption properties of aqueous solutions of straight-chain and cyclic dodecyl sulfates

The adsorption properties of aqueous solutions of sodium alkyl sulfates and their oxyethylates have been studied systematically. The effect of defined structural changes on the adsorption parameter values calculated on the basis of Frumkin's surface equation of state has been demonstrated. In particular, a comparison has been made between n-dodecyl and cyclododecyl as hydrophobic groups in sodium alkyl sulfate and its ethers. The limiting areas obtained by surface tension measurements have been discussed on the basis of the crystal structure data of n-dodecyl sulfate and theoretical calculations on the three-dimensional shape of selected conformers of cyclododecyl sulfate.

Alkanolspuren in Natriumalkylsulfaten: Nachweis und Bedeutung für die Adsorptionseigenschaften/ Alkanol Traces in Sodium Alkyl Sulfates: Detection and Importance forthe Adsorption Properties

In a review, recent results on the effect of alkanols on the adsorption properties of sodium alkyl sulphates have been presented. Significant prerequisites are sensitive methods for the determination of alkanol traces in alkyl sulphates and the preparation of surface-chemically pure alkyl sulphates. Adsorptive procedures suited to remove the surface-chemical impurities have been presented. For the trace-analytical characterization, it turned out to be advantageous to compare a sensitive HPLC method with a surface-chemical method based on the decrease of the surface tension by the trace alcohol. The HPLC method acquired allows the determination of each alcohol at high sensitivity without disturbing by the other surface-active impurities. The effect of traces of isomeric alcohols on the equilibrium isotherms and, thus, the adsorption properties of aqueous sodium alkyl sulphate solutions have been comprehensively discussed. For this particular system, the complex adsorption parameter data of Frumkin's surface equation of state have been calculated. The surface-activity parameters of the main surfactant and the minor component calculated on the basis of the generalized Szyszkowski's equation provide information on the changes of the free energy of adsorption with alkyl chain prolongation. The Traube factors calculated for the main surfactants and the trace components have been discussed.

Partial Molar Volumes of Sodium Alkyl Sulfates and Disodium α,ω-Alkanediyl Disulfates in Aqueous Solutions

Abstract The densities of aqueous solutions of sodium alkyl sulfates, H(CH2)nSO4Na (n = 1—6, 8, 10, 12) and disodium α,ω-alkanediyl disulfates, NaO4S(CH2)nSO4Na (n = 2—4, 6, 8, 10) were measured at 25 °C, and the limiting partial molar volumes were calculated. The group partial molar volume of SO4− was estimated to be 44.0 cm3 mol−1.

Micellar Compositions in Mixed Surfactant Solutions

Micellization of aqueous mixtures of alkyltriethylammonium bromide and sodium alkylsulfate in the presence of excess sodium bromide has been studied by surface tension measurements. The molecular ratio of the cationic surfactant to the anionic surfactant in the mixed micelles is deduced by applying the Gibbs-Duhem equation to the measured critical micelle concentrations. Approximately equimolar amounts of the surfactant components in the mixed micelles over a wide range of aqueous mixing ratio are found in the systems of components similar in chain lengths. Large deviations of the surfactant molecular ratio deduced by the regular solution approach (Rubingh's model) when compared with that deduced by our approach are discovered, which suggests a limitation in applying the regular solution approach to mixed systems of cationic/anionic surfactants.

On the Formation of Catanionic Surfactant Precipitate

AbstractThe morphology, structure and composition of catanionic surfactants formed during spontaneous batch precipitation from equimolar mixtures of alkylammonium chlorides and sodium alkyl sulfates, both with alkyl chains containing 10, 12 and 14 carbon atoms, were investigated by elemental, X‐ray and IR analysis. – Size distribution data are used to assess the mechanisms which control the precipitation at different stages of the process. Under experimental conditions employed (low surfactant concentration, high ionic strength) practically pure decylammonium decyl sulfate, dodecylammonium dodecyl sulfate or tetradecylammonium tetradecyl sulfate were formed. Crystalline catanionic surfactant particles exhibited low symmetry and interplanar spacings typical for lamellar structure. Great similarity of IR spectra obtained for the systems with alkyl chains containing 12 or 14 carbon atoms indicates essentially the same type of electrostatic interactions between the headgroups in these systems. – Catanionic surfactant formation could be described by a general equation of the type dV50 = atbDetermined values of the coefficient a and exponent b varied with the length of alkyl chain and the type of the rate – controlling process (growth, recrystallization and/or dissolution). Microscopic observation showed the coexistence of crystalline and liquid crystalline phase in aged systems.

Secondary structural changes of metmyoglobin and apomyoglobin in anionic and cationic surfactant solutions: effect of the hydrophobic chain length of the surfactants on the structural changes.

Secondary structural changes of metmyoglobin and apomyoglobin were examined in solutions of sodium alkylsulfates with hydrocarbon numbers of 8 and 12, and alkyltrimethylammonium bromides with hydrocarbon numbers of 10, 12, 14, and 16. The relative proportion of alpha-helical structure was estimated by the curve-fitting method of circular dichroic spectrum. The helical proportions of metmyoglobin and apomyoglobin were 82 and 63%, respectively. The shorter the hydrocarbon chain the surfactant had, the higher the concentration necessary to disrupt the secondary structures of these proteins. However, the helical proportion had a tendency to decrease down to lower values in solutions of the cationic surfactants with short hydrophobic groups. On the other hand, the alpha-helical structure of apomyoglobin was disrupted in lower concentrations of each cationic surfactant than that of metmyoglobin, although the disruptions of the same structures in both the proteins occurred in the same concentration range of each anionic surfactant. It appeared likely that the removal of the heme group unstabilized the myoglobin conformation only in the cationic surfactant solutions.

Improvement of the formation percentage of water-in-oil-in-water multiple emulsion by the addition of surfactants in the internal aqueous phase of the emulsion

In order to improve the formation percentage of w/o/w emulsions, experiments were conducted in order to elucidate the influence of the addition of various kinds of surfactants in the internal aqueous phase of the emulsion, the formation percentage of w/o/w emulsion as compared with that without additives, and with sodium chloride or sorbitol. Several physico-chemical properties of intact w/o/w emulsion or each phase, such as the osmolarity, interfacial tension and viscosity, were investigated in order to determine the governing factor in improving the formation percentage of w/o/w emulsion. w/o/w emulsion was prepared via a two-step emulsification procedure. New coccine was employed as a marker to evaluate the formation percentage of w/o/w emulsion. Sodium alkylsulfonate, sodium alkylsulfate, sodium alkylcarbonate and polyoxyethylene (20) sorbitan monooleate were used as additives in the internal aqueous phase of w/o/w emulsion as well as sodium chloride and sorbitol. The formation percentage of w/o/w emulsion was improved by increasing the concentration of the additives, viz., various kinds of surfactants in the internal aqueous phase of the emulsion, as well as sodium chloride or sorbitol. This could be attributed to a decrease in interfacial tension between the internal aqueous phase of the w/o/w emulsion and the oily phase of the emulsion.

Determination of trace amounts of alcohols in sodium alkyl sulphate mixtures using high-performance liquid chromatography and surface tension measurements

A method was developed for the simultaneous trace analysis of C 8, C 10 and C 12 alkanols in sodium alkyl sulphate mixtures. The alkanols determined after derivatization with aromatic isocyanates, RNCO (R = phenyl, 1-naphthyl, 2-anthryl). In the preferred method, microbore high-performance liquid chromatography was applied with acetonitrile—water as eluent after derivatization with 1-naphthyl isocyanate at 333 K using an RP-18 5-ωm reversed-phase column. The peaks were monitored at 222 nm.

Nitroxide-labeled ruthenium(II)-polypyridyl complexes as EPR probes to study organized systems. 1. Micellar solutions and micellization of sodium alkyl sulfates

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNitroxide-labeled ruthenium(II)-polypyridyl complexes as EPR probes to study organized systems. 1. Micellar solutions and micellization of sodium alkyl sulfatesM. Francesca Ottaviani, Naresh D. Ghatlia, and Nicholas J. TurroCite this: J. Phys. Chem. 1992, 96, 14, 6075–6083Publication Date (Print):July 1, 1992Publication History Published online1 May 2002Published inissue 1 July 1992https://doi.org/10.1021/j100193a078RIGHTS & PERMISSIONSArticle Views100Altmetric-Citations18LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts

Sodium alkyl sulfate induced deposition of methyl viologen cation radical on glassy carbon surfaces

Sodium alkyl sulfate induced deposition of methyl viologen cation radical on glassy carbon surfaces