Sodium Dodecyl Sulfate In Water Research Articles

The physicochemical properties and contact angle of sodium dodecyl sulfate in water–acetone with and without sodium nitrate (NaNO3)

Conductivity measurements at room temperature were performed to study the physicochemical behavior of anionic surfactant SDS in water and acetone–water mixture in the presence and absence of NaNO3.The concentration of SDS was 0.05 M and the concentration of NaNO3 was 0.01 M and 0.05 M. We calculated the degree of dissociation (α) and critical micelle concentration (CMC) from the pre-micellar (S1) and post-micellar slopes (S2). When acetone is added to SDS, CMC and α increase, but decreased with an increase in NaNO3.The standard free energy of micellization (ΔGm°) was evaluated using CMC and α. Micellization becomes less likely when the acetone content is higher as the negative values of ΔGm° decrease, indicating less spontaneous micellization. Due to the electrostatic repulsion of the head groups, adding salt NaNO3 decreases the CMC of SDS. A drop shape analyzer (DSA-25E) was used to measure the contact angles (CAs). For SDS, acetone and NaNO3 molecules mixed at varying concentrations, simulations were conducted.

Critical micelle concentration of SDS through DPD simulations using COSMO-RS–based interaction parameters, the thermal effects

In order to obtain the critical micellar concentration (CMC) for sodium dodecyl sulfate (SDS) in water at 288.15, 293.15, 298.15, 303.15 and 308.15 K, two approaches were employed: the first, consisting of experimental Isothermal Calorimetric Titration (ITC) and the second by using Dissipative Particle Dynamics (DPD) simulations. To determine the experimental CMC the calorimetric signal was treated with the software D/STAIN, obtaining values between 8.24 and 9.22 mM, which are in good agreement with other experimental determinations. Also the SDS micellization enthalpies found agree with previous experimental reports. The pairwise aij DPD interaction parameters, needed to run the simulations, were obtained from quantum chemistry calculations under the application of the COSMO-RS solvation scheme jointly with the Flory-Huggins theory. A series of systems with variable concentration of SDS in water were simulated for each temperature. Then, the analysis of the percentage of aggregation of SDS molecules at each temperature, enable to visualized the theoretical aggregation isotherms. By delimiting an experimental CMC window, the DPD aggregation isotherms were used to identify the concentration where either the monomeric or micellar states domain. Intersection of linear fits, in the monomeric and in the micellar regime produced theoretical CMCs values from 8.1 to 8.9 mM. These results compare favorably with the experimental determinations at each temperature.

The Influence of Ionic Liquids on Micellization of Sodium Dodecyl Sulfate in Aqueous Solutions

The micellization of sodium dodecyl sulfate (SDS) in water and aqueous solutions of NaCl (0.1 M) and three ionic liquids (IL, 0.01 M) with different side-chain length, i.e. 1,3-dimethylimidazolium chloride, 1-ethyl-3-methylimidazolium chloride, and 1-butyl-3-methylimidazolium chloride was investigated in the temperature range from 288.15 to 328.15 K using isothermal titration calorimetry (ITC). Thermodynamics of micellization was studied by the fitting of the mass-action model to the ITC data. The micellization of SDS in all the studied systems is an entropy-driven at lower temperatures and an enthalpy-driven at higher temperatures. It was also found that with the increasing nonpolar character of IL the interactions between the SDS should be stronger leading to more negative Gibbs free energy and enthalpy of micellization. To obtain information about the micellar charge, the conductivity and zeta-potential measurements were performed at 298.15 K. It is assumed that the charge screening between negative sulfate heads is more efficient in the presence of ILs due to their possible incorporation into the micellar structure reflecting in less negative zeta-potential of micelles comparing to SDS in water and consequently higher degrees of micelle ionization due to the larger portion of sodium ions in solution.

Preparation and Some Physicochemical Properties of Water–Surfactant–Halohydrocarbon Microemulsions Suitable for the Creation of Combined Fire Extinguishing Agents

The research findings related to synthesis and study of water–sodium dodecyl sulfate–1-pentanol–triethanolamine–2-iodoheptafluoropropane and water–sodium dodecyl sulfate–1-pentanol–triethanolamine–1,2-dibromotetrafluoroethane microemulsions at the standard temperature were summarized. Use of microemulsions provides a promising means of combining with water chemically active inhibitors such as halohydrocarbons, which are water-immiscible under ambient conditions. This affords fire extinguishing agents integrating different flame suppression mechanisms: chemical inhibition of the combustion reaction and flame cooling. The electrical conductivities and heat capacities of the microemulsions synthesized were determined and used for analyzing the structural changes caused in them by changes in their composition. Using the dynamic light scattering method, the size of the microdroplets of the microemulsions was determined, and their size distribution was examined. Based on the data obtained, the fire extinguishing performance of the microemulsions (cooling capacity, possible applications, and mechanism of action) was described. Laboratory tests of the fire extinguishing efficiency of the microemulsions were carried out.

Micelle Encapsulation of Ferromagnetic Nanoparticles of Iron Carbide@Iron Oxide in Chitosan as Possible Nanomedicine Agent

In this work, the synthesis and characterization of core/shell nanoparticles of iron carbide@iron oxide (Fe3C/γ-Fe2O3) encapsulated into micelles of sodium dodecylsulfate and oleic acid and stabilized with chitosan was developed. The materials were sonosynthesized at low intensities using standard ultrasonic baths with iron pentacarbonyl (Fe(CO)5) and oleic acid as iron source and hydrophobic stabilizer, respectively; obtaining nanoparticles with a hydrodynamic diameter of 19.71 nm and polydispersive index (PDI) of 0.13. The iron carbide@iron oxide nanoparticles (ICIONPs) in oleic acid were used as the organic phase during the self-assemble of nanoemulsion with sodium dodecylsulfate in water to obtain the metastable micelles. The final step involved the stabilization of the micelles using low molecular weight chitosan solution at 2% in acetic acid by ultrasonication bath. The nanosystem showed a hydrodynamic diameter of 185.30 nm, a PDI of 0.15 with a superficial charge ζ of 36.70 mV. Due to the magnetic, physical and chemical properties previously measured of the ICIONPs, it is believed that this type of nanoparticles can be used as a possible nanomedicine agent.

Aqueous Foams in the Presence of Surfactant Crystals.

Aqueous foams are used extensively in many fields and anionic surfactants are commonly used foaming agents. However, potential trouble may arise when they are utilized in hard water areas and/or at low temperatures. Anionic surfactants, like sodium dodecyl sulfate (SDS), may precipitate in the form of crystals when the concentration of divalent counterions such as Mg2+ exceeds a certain limit. In an attempt to prepare ultrastable foams containing precipitated crystals, the behavior of SDS in water was systematically investigated as a function of surfactant concentration at different concentrations of Mg(NO3)2 prior to a study of their foam properties. We quantitatively study the conversion of surfactant micelles to crystals and the redissolution of crystals into micelles. It was found that the presence of surfactant crystals reduced the initial foam volume and foam half-life but greatly improved the long-term stability of foams. Foam studies were also conducted for the supernatant and sediment isolated from crystal dispersions so that the importance of surfactant crystals to foam stability could be established. Despite the foamability of a sediment being low, an order of magnitude increase in foam half-life was related to the coverage of bubble surfaces by surfactant crystals. Both rapid cooling and ultrasonication were shown to influence the surfactant crystal shape and size with an impact on foam properties.

Temperature Dependence of Micellization Properties of Binary Mixtures of Sodium Decylsulphate with Sodium Dodecylsulphate in Water

Conductance measurement method has been used to determine the critical micelle concentration (CMC) and counterion binding constant values of binary mixtures of sodium decylsulphate (SDeS) with sodium dodecylsulphate (SDS) in water at four different temperatures ranging from 298 K to 313 K at 5 K intervals. Rubingh′s model has been used to calculate the mixed micellization properties viz. mixed micelle composition, activity coefficient of the components, and mutual interaction parameter between the components. Variation of these mixed micellization properties with temperature has been studied. The studied binary surfactant mixtures show attractive interaction between the components and it decreases with increase in temperature, which is an interesting trend. Thermodynamic parameters of mixed micellization have also been calculated. The enthalpy (ΔH°mic) and entropy (ΔS°mic) of micellization compensate each other.

Discerning the Structure Factor of Charged Micelles in Water and Supercooled Solvent by Contrast Variation X-ray Scattering.

Sodium dodecyl sulfate (SDS) is a well-known anionic surfactant that forms micelles in various solvents including supercooled sugar-urea melt. Here, we explore the application of contrast variation small-angle X-ray scattering (SAXS) in discerning the structure and interactions of SDS micelles in aqueous solution and in a room-temperature supercooled solvent. The SAXS patterns can be analyzed in terms of a core-shell ellipsoid model. For aqueous SDS micelles, at low volume fractions, the features due to intermicellar interaction, S(q), in the SAXS pattern are poorly resolved because of the prominent contribution from shell scattering. Increasing the electron density of the solvent by the addition of the urea or fructose-urea mixture (at a weight ratio of 6:4) permits the systematic variation of shell scattering without influencing the structure drastically. For a 10% solution of SDS in water, the contribution from the shell can be completely masked by the addition of 40% urea or fructose-urea mixture. The fructose-urea mixture is a preferred additive as it can vary the scattering length density over a wide range and serves as a matrix to form supercooled micelles. The structural parameters of micelles in supercooled fructose-urea melt are obtained from contrast variation SAXS, small-angle neutron scattering, and high-resolution transmission electron microscopy.

Structure of Micelles of Sodium Dodecyl Sulphate in Water: an X-ray and Dynamic Light Scattering Study

(PDF) Graphical Abstract: Aqueous micellar solutions of sodium dodecyl sulphate were investigated using X-ray scattering technique by a model-independent approach and dynamic light scattering in the concentration range 0.008 – 0.1 M. The obtained results are discussed in the framework of the concept of polyamorphous transition between ensembles of water clusters of low and high density levels. Polyamorphous transition accompanies the formation of dual structures of contact and separated by water micelles with different rates of diffusion.

Magnetite Nanoparticles in Hybrid Micelles of Polylactide-block-polyethylene Oxide and Sodium Dodecyl Sulfate in Water

Magnetite nanoparticles have been obtained in hybrid micelles of polylactide-block-polyethylene oxide (PL-b-PEO) and sodium dodecyl sulfate (SDS) in a one-stage process. Dynamic light scattering, transmission electron microscopy, and small-angle X-ray scattering data show that hybrid micelles form micellar associates, and the size of magnetite nanoparticles in hybrid micelles of the block-copolymer varies from 0.5 to 10 nm. The specific magnetization of solid samples has been measured.

Effect of glycerol with sodium chloride on the Krafft point of sodium dodecyl sulfate using surface tension

The effect of glycerol with sodium chloride (NaCl) on the phase behaviour of sodium dodecyl sulfate (SDS) near the Krafft point was studied by surface tension analysis using the pendant drop method. The critical micelle concentration (CMC) and Krafft Temperature (TK) of SDS in water: glycerol mixtures, across the full composition range, and in NaCl solutions within 0.005–0.1 M were obtained. The pendant drop method successfully allowed us to determine the Krafft point of SDS in high glycerol systems where other traditional methods (e.g. conductivity) have been ineffective. Overall the addition of glycerol increases the CMC and the TK, thus shifting the Krafft point of SDS to higher temperatures (increasing crystallisation temperatures) and higher SDS content in the presence of glycerol, which is interpreted as a result of the reduction in solvent polarity which opposes micellization. The addition of NaCl to the SDS – water-glycerol systems brings the CMC back down, while having no significant effect on the TK. Our results establish a robust route for tuning the Krafft point of model surfactant SDS by adjusting solvent quality and salt content.

Solvation dynamics in SDS micelle revisited with femtosecond time resolution to reveal the probe and concentration dependence

The present work is devoted to understand the probe and surfactant concentration dependence of solvation dynamics in sodium dodecyl sulfate (SDS) micelle. The average solvation times are found to follow the hydrophobicity of the probe and it was concluded that the location of probe inside SDS micelle determines the solvation time. We also studied the solvation dynamics in varying concentrations of SDS in water and found a small but definite increasing trend in solvation time. Rotational diffusion time of the fluorescent probe did not change with change in SDS concentration, which hinted that distortion in the shape of micelle may be the reason behind variation of solvation time. The analysis of solvent response function in all the cases hints towards the existence of an ultrashort (∼100 fs) time component due to the libration motion of water molecules.

Effect of TritonX-100 on the aggregation behavior of SDS in water

ABSTRACTThe phase behavior patterns and microstructures of surfactant systems containing sodium dodecyl sulfate (SDS)/TritonX-100/H2O were investigated under a polarizing microscope. Ternary mixtures of SDS/TritonX-100/H2O form two types of well-ordered lyotropic liquid crystals: a hexagonal phase linked to the SDS/water axis and a lamellar phase located at the corner of their phase diagram. Surface tension measurements were conducted for TritonX-100 in the SDS solutions. In the SDS/TritonX-100/H2O system, transition points were found in the surface tension concentration curves at different quality ratios. On the basis of the critical micelle concentration values, the thermodynamic parameters of the aggregate formation, namely, , , and , were estimated. Results show that the addition of TritonX-100 is beneficial to the formation of surfactant aggregates, and thermodynamic data indicate that the micellization of binary mixture of SDS/TritonX-100 in aqueous solution is an entropy-driven spontaneous process. Therefore, the addition of TritonX-100 in SDS aqueous solutions may have potential applications in nanomaterial preparation.

Methane gas hydrate kinetics with mixtures of sodium dodecyl sulphate and tetrabutylammonium bromide

The effect of combining a thermodynamic promoter, tetrabutylammonium bromide (TBAB), with a kinetic promoter, sodium dodecyl sulphate (SDS), to a methane clathrate system was investigated. Kinetic growth experiments were conducted in a semi‐batch stirred tank crystallizer at driving forces of 1500 kPa using a range of 100 to 1500 ppm SDS and 200 to 200 000 ppm TBAB. Solutions containing low concentrations of TBAB in water reduced methane hydrate growth rates up to 55 % for 1250 ppm TBAB compared to pure water. Solutions containing 900 ppm SDS in water enhanced the growth rate by 880 % compared to pure water. Solutions were then tested combining both promoters. The gradual addition of SDS from concentrations between 100 to 1250 ppm to low‐concentration TBAB systems between 200 to 1250 ppm was initially found to reduce growth kinetics, but eventually increased the growth rates once a threshold SDS concentration was reached. In all cases, the promoting effect of the SDS was more pronounced in the absence of the TBAB. The growth kinetics of systems containing 5 and 20 wt% TBAB also followed a similar inhibition‐promotion trend with the SDS concentration. An increase of 177 % in the gas consumption rate was observed when 1500 ppm SDS was added to the 20 wt% TBAB clathrate system. This work demonstrates that SDS can be added to a TBAB‐water‐methane system to enhance gas consumption rates, but care must be taken to ensure that the concentration of the additives places the system in a promotion regime.

Micellization of sodium dodecyl sulphate in presence and absence of alkali metal halides at different temperatures in water and methanol-water mixtures

The micellization of sodium dodecyl sulphate (SDS) in presence and absence of KCl, KBr, NaBr and NaCl in water and methanol-water mixtures containing 8, 16, 25 and 34wt% of methanol at 298.15 to 323.15K have been assessed from conductometric measurements. The concentrations of SDS were varied from ~0.001 to ~0.05molL−1 and salts concentration was 0.01molL−1. The critical micelle concentration (CMC) of SDS in presence and absence of salts in water as well as in methanol-water mixtures are found to increase with the increase in temperature and found to decrease with the addition of salts. The CMC of SDS in water and methanol-water mixtures in presence of studied salts is found in the order NaCl>NaBr>KCl>KBr.Thermodynamic properties of micellization such as the standard free energy of micellization, standard enthalpy of micellization, the standard entropy of micellization, the standard free energy of transfer and heat capacity of micellization of SDS in presence and absence of salts have been examined. The micellization of SDS with presence and absence of salts has been assessed in terms of different solvent parameters. The solvophobic parameters have been presented.

Effect of methanol on the surface tension and viscosity of sodiumdodecyl sulfate (SDS) in aqueous medium at 298.15–323.15 K

The surface tension and viscosity of sodiumdodecyl sulfate (SDS) in water and in 0.10, 0.20, 0.30 and 0.40 volume fractions of methanol in water at 298.15 K, 308.15 K, 318.15 K and 323.15 K are measured. The critical micelle concentrations (CMCs) of the solutions are determined from both the surface tension and viscosity. The critical micelle concentrations (CMC) of SDS in water as well as in methanol-water mixture are found to increase with increase in temperature. The CMC of SDS increases with the addition of methanol. The surface properties, such as the surface excess concentration Гmax, minimum surface area Amin, surface pressure πcmc and packing parameter P are calculated from the surface tension data. Viscosity B coefficients of the SDS solutions are calculated using the relative viscosity data.

Intermolecular Interactions in Self-Assembly Process of Sodium Dodecyl Sulfate by Vertically Polarized Raman Spectra

Molecular self-assembly is extremely important in many fields, but the characterization of their corresponding intermolecular interactions is still lacking. The C—H stretching Raman band can reflect the hydrophobic interactions during the self-assembly process of sodium dodecyl sulfate (SDS) in aqueous solutions. However, the Raman spectra in this region are seriously overlapped by the OH stretching band of water. In this work, vertically polarized Raman spectra were used to improve the detection sensitivity of spectra of C—H region for the first time. The spectral results showed that the first critical micelle concentration and the second critical micelle concentration of SDS in water were 8.5 and 69 mmol/L, respectively, which were consistent with the results given by surface tension measurements. Because of the high sensitivity of vertically polarized Raman spectra, the critical micelle concentration of SDS in a relatively high concentration of salt solution could be obtained in our experiment. The two critical concentrations of SDS in 100 mmol/L NaCl solution were recorded to be 1.8 and 16.5 mmol/L, respectively. Through comparing the spectra and surface tension of SDS in water and in NaCl solution, the self-assembly process in bulk phase and at interface were discussed. The interactions among salt ions, SDS and water molecules were also analyzed. These results demonstrated the vertically polarized Raman spectra could be employed to study the self-assembly process of SDS in water.

Molecular dynamics study of the potential of mean force of SDS aggregates.

In our previous study, all-atomistic molecular dynamics (MD) calculations have been carried out for the aggregation of ionic sodium dodecyl sulfate in water [S. Kawada et al., Chem. Phys. Lett. 646, 36 (2016)]. Aggregates of 20-30 dodecyl sulfate ions were formed within a short MD run for 10 ns. However, further aggregation did not occur despite a long MD calculation for more than 100 ns. This suggests that strong electrostatic repulsive interactions between the aggregates prevent the fusion of the aggregates. In the present study, mean force and potential of mean force acting between two aggregates with aggregation number N = 30 were evaluated as a function of their separation by MD calculations. The repulsive force becomes strong with decreasing distance between the two aggregates before they merge into one. An origin of the repulsive force is an electric double layer formed by the sulfate group and counter sodium ions. Strength of the repulsive force is in good agreement with the theoretical value given by the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Once the aggregates establish contact, the force between them turns to be a large attractive force that can be explained by the interfacial tension. In order to form a single micelle from the two aggregates, it is necessary for them to climb over a free energy barrier of 23 kJ/mol. Once, the barrier is overcome, the micelle is stabilized by ∼200 kJ/mol. The time constant of aggregation evaluated from the calculated free energy barrier was about 28 μs at the concentration in our previous study.

Effect of biological buffers on the colloidal behavior of sodium dodecyl sulfate (SDS)

This study investigates the influence of three commonly used buffers (TRIS, TES and TAPS) on the conductivities and the colloidal behavior of the aqueous solutions containing a surfactant, sodium dodecyl sulfate (SDS). To find the effect of these buffers on the aggregation behavior of the aqueous SDS solutions, we experimentally determined the conductivities of the solutions containing different concentrations of SDS (0.002M–0.025M) in water and in 0.2M, 0.5M, and 1.0M TRIS, TES, and TAPS buffers, respectively, at 298.2K under atmospheric pressure. To get insight into the effect of the buffers on the aggregation behavior of the aqueous SDS solutions, the critical micelle concentration (CMC) values of the aqueous solutions are estimated from the experimental results of conductivity measurements. Interestingly, in comparison with the CMC of SDS in water, the presence of TRIS is found to increase the CMC, whereas the addition of TES or TAPS is found to decrease the CMC, especially at higher concentration (1.0M). The influence of the buffers on the CMC or aggregation of the SDS is further characterized by calculating various aggregation parameters such as the degree of ionization of the micelle (αm), the degree of counter ion binding in micelle (fm), and the standard Gibbs free energy of micellization (ΔG°m) for all the studied systems. Moreover, the outcomes from the conductivities measurement are reconfirmed by using the fluorescence probe analysis.

The Effect of Aniline Hydrochloride Hydrotrope on the Phase Behavior of SDS/Water System

AbstractThe aim of this work was to determine the detailed phase behavior of the sodium dodecyl sulfate/aniline hydrochloride/water system as a function of concentration of sodium dodecyl sulfate (SDS), aniline hydrochloride (AHC) to sodium dodecyl sulfate molar ratio (R = [AHC]/[SDS]) and temperature. Phase behavior information was obtained via polarizing microscopy, differential scanning calorimetry (DSC), cryo‐scanning electron microscopy (Cryo‐SEM) and oscillatory linear rheological measurements with good agreement among these techniques. It is well known that SDS in water forms spherical micelles at concentrations lower than 40 wt% and temperatures above its Krafft temperature (Tk = 16–21 °C). In this region, the SDS/water system exhibits Newtonian rheological behavior, which is characteristic of spherical micellar solutions. The addition of the hydrotrope, aniline hydrochloride, to SDS aqueous solutions produces a viscosity increase in this system as R augments, and a maximum of about five orders of magnitude was found at R = 0.47 for 5 wt% SDS at 20 °C. Moreover, the system shows a transition from viscous to strong viscoelastic behavior. These changes in the rheological behavior are produced by the transitions from sphere to rodlike micelles, which are induced by the hydrophobicity of AHC causing it to be absorbed into the core and the hydrophilic interface of the micelles, which screens the repulsions between the charged head groups.