Aqueous Solutions Of Sodium Dodecyl Sulfate Research Articles

Investigations on the formation kinetics of semiclathrate hydrate of methane in an aqueous solution of tetra-n-butyl ammonium bromide and sodium dodecyl sulfate in porous media

ABSTRACTNatural gas hydrate is considered to be an attractive sustainable energy resource for the world. Hydrate as a technology can be of immense importance for various industrial processes, such as multicomponent natural gas separation, gas storage and transportation, and carbon dioxide capture from flue gases and sequestration. A variety of hydrate additives, which includes promoters (thermodynamics and kinetics) and porous media, are being researched to improve the hydrate formation kinetics. However, studies involving the combinations of these are rare in the open literature. In this work, the formation kinetics of methane hydrate/semiclathrate hydrate using tetra-n-butyl ammonium bromide (TBAB) and sodium dodecyl sulfate (SDS) aqueous solutions at various concentrations in a porous medium containing silica sand at initial hydrate formation pressures (7.5 and 5.5 MPa) and temperatures (273.65 and 276.15 K) have been investigated. All the experiments were conducted using 75% water saturation. Various kinetics parameters, such as gas uptake, gas-to-hydrate conversion, and induction time, have been reported. It was found that the combination of TBAB+ SDS showed favorable hydrate formation kinetics in porous media than the TBAB system. This work provides information for further studies involving semiclathrate hydrate applications for various industrial processes.

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.

Wplyw kompleksow anionowych surfaktantow z poliwinylopirolidonem tworzonych w roztworach wodnych na wlasciwosci fizykochemiczne i uzytkowe szamponow

Based on the analysis of published results of studies on the complexes of polymers with surfactants in aqueous solutions, shampoo formulations containing sodium dodecyl sulfate (SDS) and polyvinylpyrrolidone (PVP), which are mild to the skin, were developed. The measurements of surface tension, foamability and zein number confirmed that the aqueous solutions of PVP and SDS may be used as bases for shampoo with low irritation potential. The most favorable evaluation of physicochemical and sensory tests was obtained for a shampoo containing PVP90 (termed the original shampoo). A comparison of selected functional properties of the original product with the commercial product was performed. Both shampoos were of comparable quality, but the zein number (ZN), which is a measure of irritation potential, was reduced by more than 30 % compared to the commercial shampoo.

STABILITY OF FOAMS CONTAINING DIESIL FUEL

The comparative characteristic of the stability of foams formed by sodium dodecylsulfate and gelatin at their various concentrations at the presence of the diesel fuel under the action of an applied pressure drop was carried out in this work. It was shown that the change in the gelatin/ surfactant ratio in the initial solution changed the stability of such foams at the presence of an organic liquid. The surfactant and protein concentrations when these dispersions are more stable at the presence of the organic phase were determined. The isolated foam films obtained from a solution of sodium dodecyl sulfate + gelatin / diesel fuel were studied. It was shown that there was no correlation between the stability of the isolated film and the foam under the action of applied pressure drops: the films in contact with diesel fuel retained considerable stability, unlike the foams obtained from this aqueous solution of gelatin and surfactant in the presence of said organic substance. The coefficients of initial spreading of diesel fuel on the surface of an aqueous solution containing gelatin and surfactant were calculated. The change in the interfacial energy at the interface of the aqueous solution of sodium dodecylsulfate + gelatin/ diesel fuel with time when changing of the surfactant: protein ratio in the initial solution and different concentrations of the organic liquid was investigated. The change in the interfacial tension at the interface of the aqueous solution of sodium dodecylsulfate + gelatin/ diesel fuel over time was accompanied by a significant decrease in the stability of foams obtained from aqueous solutions containing gelatin and an ionic surfactant. If the interfacial tension did not change or slightly decreased, the foams containing diesel fuel remained stable.Forcitation:Vilkova N.G., Mishina S.I., Dorchina O.V. Stability of foams containing diesil fuel. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 6. P. 48-53

Thermochemistry of the Dissolution of Dipeptides Containing DL-α-Alanine in Aqueous Solutions of Sodium Dodecyl Sulfate at 298.15 K

Enthalpies of the dissolution of DL-α-alanylglycine (AlaGly), DL-α-alanyl-DL-α-alanine (AlaAla), DL-α-alanyl-DL-α-valine (AlaVal), and DL-α-alanyl-DL-norleucine (AlaNln) in an aqueous solution of sodium dodecyl sulfate (SDS) at SDS concentration of m = 0–0.07 mol kg−1 and temperature Т = 298.15 K are measured via calorimetry. The standard values of the enthalpy of dissolution (ΔsolH m ) and the transfer of dipeptides (ΔtrH m ) from water to aqueous SDS solutions are calculated using the experimental data. The dependences of ΔsolH m and ΔtrH m the SDS concentration at a constant concentration of dipeptide are established. Thermochemical characteristics of the transfer of AlaGly, AlaAla, AlaVal, and AlaNln in the investigated range of SDS concentrations are compared. The results are interpreted by considering ion–ion, ion–polar, and hydrophobic–hydrophobic interactions between SDS and dipeptide molecules.

Water absorption by decellularized dermis

Water absorption by decellularized dermis was investigated and compared with biopolymer and synthetic polymer hydrogels (glutaraldehyde-crosslinked gelatin and crosslinked poly(acrylamide) hydrogel, respectively). Porcine dermis was decellularized in an aqueous sodium dodecyl sulfate (SDS) solution. Histological evaluation revealed that the SDS-treated dermis has much larger gaps between collagen fibrils than non-treated dermis, and that water absorption depends on these gaps. Decellularized dermis has low water absorptivity and the absorption obeys Fick's second law. During absorption, the water diffusion rate decreases with time and occurs in two steps. The first is rapid absorption into the large gaps, followed by slow absorption by the collagen fiber layer. Because of the gaps, decellularized dermis can absorb more water than native dermis and shows different water absorption behavior to glutaraldehyde-crosslinked gelatin and crosslinked poly(acrylamide) hydrogels.

A Simple Method for Synthesizing Ultra-high-molecular-weight Polystyrene through Emulsion Polymerization Using Alkyl-9-BBN as an Initiator

Styrene emulsion polymerization using an alkyl-9-BBN, synthesized by reacting 9-BBN (9-borabicyclo-[3.3.1]-nonane) and styrene, in an aqueous sodium dodecyl sulfate (SDS) solution was studied. Ultra-high-molecular-weight (> 1.0 × 107) polystyrene was synthesized using a radical initiator formed through the aerobic oxidation of this alkyl-9-BBN in a high yield (> 80%). The kinetics of this emulsion polymerization of styrene with the alkyl-9-BBN was investigated. We confirmed that in the initial stage of the polymerization, the initial reaction rate followed first-order kinetics. The activation energy for this emulsion polymerization of styrene was approximately 56.2 kJ/mol.

Temperature-responsive Pickering foams stabilized by poly(N-isopropylacrylamide) nanogels

Poly(N-isopropylacrylamide) (PNIPAM) nanogels were synthesized by emulsion polymerization using sodium dodecyl sulfate (SDS). After removal of SDS by dialysis, the surface tensions of the PNIPAM nanogel aqueous dispersions were measured at various temperatures by the pendant-drop method, and it was found that the surface tensions of the nanogel dispersion below the lower critical solution temperature (LCST) of PNIPAM were much smaller than those of water and comparable to those of the SDS aqueous solution. The stability of the aqueous foams generated by nitrogen bubbling thorough the PNIPAM nanogel dispersion was investigated below and above the LCST of PNIPAM. The foam prepared below the LCST was stable in some degree, whereas almost no foam was formed above the LCST. Moreover, the foam prepared below the LCST was quickly collapsed by changing the temperature above the LCST. This rapid defoaming represents that the surface activity of the PNIPAM nanogel can be switched off by the temperature increase across the LCST.

Disruption of human stratum corneum lipid structure by sodium dodecyl sulphate.

Surfactants are major ingredients of body soaps and cleansers, and such harsh ones have been demonstrated to damage the skin. Stratum corneum (SC), the outermost barrier of the skin layer, is rich in intercellular lipids. This lipid structure can be disrupted by surfactants, impairing the barrier function of the skin. Thus, we investigated the surfactant-induced disruption of the intercellular lipid structure of human SC at the molecular level using synchrotron X-ray diffraction. SC samples from the breast of female Caucasians were treated with sodium dodecyl sulphate (SDS) and analysed by small-angle and wide-angle X-ray diffraction. We found that an aqueous SDS solution affected the long lamellar structure, which became disorganized. The final disordered lipid state was reached through two or more types of structural change. We propose that the disordered lipid state results from incorporation of SDS into the long lamellar structure. In contrast, the lattice constants in the short lamellar and the hydrocarbon-chain packing structures remained almost unchanged after SDS treatment. We conclude that the disruption of the long lamellar structure plays a key role in the damage to the SC caused by detergents. To our knowledge, this is the first report to clarify the details of the disorganization of the intercellular lipid structure upon surfactant application. The knowledge obtained herein may allow the development of skin restoration methods and cleanser products that do not affect skin barrier functions.

Motion modes of two self-propelled camphor boats on the surface of a surfactant-containing solution

HypothesisThe existence of a surface tension difference and a surface flow around self-propelled objects, such as camphor boats, has been confirmed by many studies. However, the interactions in the collective motion of several camphor boats have not been explicitly discussed. Here, a model system of two camphor boats was investigated for the first time from the viewpoint of surface tension and surface flow. ExperimentsThe behavior of one fixed boat and one movable boat on a sodium dodecylsulfate aqueous solution in an oval track has been studied as a model system of two-body interactions. The surface tension around the movable boat was measured using the non-invasive, double-beam quasi-elastic laser scattering method. The Marangoni surface flow was quantitatively estimated using a mock boat in order to evaluate the net repulsive interaction between the two boats. FindingsWe succeeded in controlling the motion of the two camphor boats by varying the boat characteristics and the surfactant concentration. The balance/unbalance between the surface tension distribution and the surface flow around the boats was found to drive two different behavior modes: stationary and oscillatory. These results allow us to gain further insight into the dynamics of the interactions in the collective behavior of autonomous inanimate objects.

The influence of aqueous sodium dodecyl sulphate solution in the photoresponsivity of nitrogen doped graphene oxide photodetector

The homogeneity and agglomeration in graphene based photodetector plays an important role in the photoconduction. The influence of sodium dodecyl sulphate (SDS) solution in nitrogen doped graphene oxide (N-GO) is studied based on the photoresponsivity behaviour. One step hydrothermal method and drop casting technique are utilized to obtain N-GO photodetectors. High photoresponsivity about 1000 folds is achieved in N-GO prepared with SDS solution (N-GO/SDS) compared to the N-GO prepared without SDS solution. Raman spectrum also revealed a high intense D and G band as well as a slightly broaden 2D band due to sp2 hybridization. The fabricated device has exhibited wide range of responsivity to infrared (IR) laser 974 nm pulse and illumination. Real time current measurement in N-GO and current–voltage (I-V) characteristics in N-GO/SDS showed a significant photoconduction due to laser 974 nm illumination. The external quantum efficiency (EQE) in the N-GO/SDS solution is about 394830% compared to N-GO prepared without SDS, which is only 272%. The evaluated fall time at frequency modulation of 0.1 and 1 Hz for direct current (dc) bias voltage of 5.0 V found to be shorter compared to that of 2.5 V, whereas the fall time at high frequency modulation at 5000 Hz exhibited similar time around 77 μs.

Protein extraction into the bicontinuous microemulsion phase of a Water/SDS/pentanol/dodecane winsor-III system: Effect on nanostructure and protein conformation

Bicontinuous microemulsions (BμEs), consisting of water and oil nanodomains separated by surfactant monolayers of near-zero curvature, are potentially valuable systems for purification and delivery of biomolecules, for hosting multiphasic biochemical reactions, and as templating media for preparing nanomaterials. We formed Winsor-III systems by mixing aqueous protein and sodium dodecyl sulfate (SDS) solutions with dodecane and 1-pentanol (cosurfactant) to efficiently extract proteins into the middle (BμE) phase. Bovine serum albumin (BSA) and cytochrome c partitioned to the BμE phase at 64% and 81% efficiency, respectively, producing highly concentrated protein solutions (32 and 44gL−1, respectively), through release of water and oil from the BμEs. Circular dichroism spectroscopic analysis demonstrated that BSA underwent minor secondary structural changes upon incorporation into BμEs, while the secondary structure of cytochrome c and pepsin underwent major changes. Small-angle x-ray scattering (SAXS) results show that proteins promoted an increase of the interfacial fluidity and surface area per volume for the BμE surfactant monolayers, and that each protein uniquely altered self-assembly in the Winsor-III systems. Cytochrome c partitioned via electrostatic attractions between SDS and the protein’s positively-charged groups, residing near the surfactant head groups of BμE monolayers, where it decreased surfactant packing efficiency. BSA partitioned through formation of SDS-BSA complexes via hydrophobic and electrostatic attractive interactions. As the BSA-SDS ratio increased, complexes’ partitioning favored BμEs over the oil excess phase due to the increased hydrophilicity of the complexes. This study demonstrates the potential utility of BμEs to purify proteins and prepare nanostructured fluids possessing high protein concentration.

Thermodynamic characteristics of the dissolution of glycine, glycylglycine, and glycylglycylglycine in aqueous solutions of sodium dodecyl sulfate at Т = 298.15 K

the enthalpies of dissolution of glycine (Gly), glycylglycine (GlyGly), and glycylglycylglycine (GlyGlyGly) are measured in aqueous solutions of sodium dodecyl sulfate (SDS) at SDS concentrations m = 0–0.7 mol kg−1 and Т = 298.15 K by means of calorimetry. The obtained data are used to calculate the standard values of enthalpies of dissolution (Δsol H m ) and enthalpies of transfer (Δtr H m ) of glycine and its oligomers from water to SDS aqueous solutions. The dependences of Δsol H m and Δtr H m on SDS concentration in an aqueous solution at a constant concentration of glycine and its oligomers are determined. A comparative analysis of the thermodynamic characteristics of Gly, GlyGly, and GlyGlyGly transfer within the studied range of SDS concentrations is performed. The results are interpreted in terms of ion–ion, ion–polar, and hydrophobic interactions between SDS and molecules of glycine and its oligomers.

Measurement of the amount and rate of methane dissolution in pure water and aqueous solution of SDS + multi-wall carbon nanotubes + β-cyclodextrin

ABSTRACTIn this paper, the impact of the mixture of sodium dodecyl sulfate (SDS) + multi-wall carbon nanotubes (MWCNTs) + β-cyclodextrin on the quantity and initial rate of methane dissolved in water is investigated. The experiments were performed at a temperature range of 278.15–303.15 K and an initial pressure of 0.5 MPa. The experimental results show that simultaneous utilization of β-cyclodextrin (0.01 mass fraction), MWCNTs (0.0005 mass fraction), and SDS (0.001 mass fraction) at 278.15 K increases the amount and the rate of methane dissolution in water by 29.90% and 173.78%, respectively, compared to pure water. An increase in the temperature decreases the quantity and the initial rate of methane dissolution in all solutions containing additives. However, no consistent relationship is observed between the temperature and the enhancement percentage of solubility of methane in solutions containing additives.

Preparation and Studies of Electrodeposited CuSe Thin Films

Cathodic electrodeposition in the presence of sodium dodecyl-sulphate in aqueous solution was used to prepare CuSe thin film deposited on titanium substrates. The effect of deposition potential, concentration<br />and deposition time were studied to determine the optimum condition for the electrodeposition process. The films were characterized by X-ray diffractrometry. Scanning electron microscopy was used to study<br />the morphology of the deposits. The photoresponse of the films prepared was analysed using linear sweep voltammetry in the presence of sodium thiosulphate.

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.

Molecular modeling of ionic aggregates at several concentrations of SDS in aqueous solution

The results of molecular modeling of ionic surfactant self-aggregation in sodium dodecyl sulphate (SDS) aqueous solutions, both salt-free and with addition of NaCl, are reported. The modeling has been based on all-atom molecular dynamics simulations at several SDS concentrations. Formation of one or three ionic aggregates of different size has been observed in the molecular dynamics runs. The computed trajectories of molecules and ions have been used to study the effects of aggregation on local densities of water molecules and counterions, and on the diffusivities of the aggregates themselves. With finding the mean force potential, the degree of counterion binding for aggregates with different aggregation numbers has been estimated. The results have been compared with the classical square-gradient density functional computations for a single ionic micelle in polar solvent. In addition, the influence of size of the simulation box on the transport properties of SDS aggregates has been investigated. In particular, we have found how the diffisivity of an ionic aggregate with a given aggregation number depends on the total surfactant concentration. The diffusivities of aggregates with aggregation numbers 16, 32, 48, and 64 at fixed total surfactant concentration have been computed. With the help of the Stokes-Einstein relation, the viscosity of the micellar solution at different total surfactant concentrations has been calculated. Time dependencies of the number of aggregates in the simulation box and of the average aggregation number during the self-assembly of surface active ions have been studied.

Effect of the aniline hydrochloride hydrotrope on the microstructure of SDS/water system: Linear rheological behavior

In this work, the linear viscoelastic properties of the sodium dodecylsulfate/aniline hydrochloride/water system were examined in detail as a function of aniline hydrochloride (AHC) to sodium dodecyl sulfate (SDS) molar ratio (R=[AHC]/[SDS]), SDS concentration and temperature. SDS aqueous solutions undergo a structural transition from sphere to rodlike micelles and subsequently to a viscoelastic network of wormlike micelles induced by the hydrotrope AHC at low and intermediate R molar ratios (i.e., R=0.1–0.6 for 5wt.% SDS), which screens the repulsions between the neighboring charged head groups. The rheological response indicates that at low R molar ratios and constant surfactant concentration, the rheological behavior of the system is predominantly viscous (G′<G″). However, upon increasing R, the elastic behavior predominates (G′>G″) and a maximum of the absolute value of the zero frequency complex viscosity (|η0*|) is observed, which suggest that the micellar length also goes through a maximum. The region of the elastic behavior diminishes at even greater R molar ratios and a predominantly viscous behavior appears again. This drop in |η0*| can be attributed to the transition from linear to branched wormlike micelles that conform the tridimensional viscoelastic network. The dynamic behavior of the system was analyzed in terms of the Granek-Cates theory, which indicates that the viscoelastic network is in the slow-breaking limit. Under these conditions, reptation is found to be the controlling relaxation mechanism for this system.

Fabrication of hollow polymer particles using emulsions of hydrocarbon oil/fluorocarbon oil/aqueous surfactant solution

We have examined the influence of sodium dodecylsulfate (SDS) on the formation of emulsions consisting of hydrocarbon oil/fluorocarbon oil/water and the fabrication of hollow polymer particles by simple radical polymerization using these emulsions. Emulsions consisting of ternary mixtures of styrene/perfluoro-n-octane (PFO)/aqueous SDS solution are prepared at 80°C. Light and fluorescence microscopy observations indicate that the ternary mixtures are O/W (oil-in-water)-type emulsions. It is found that PFO droplets are present on the surface of styrene droplets. In other words, the oil droplets show Janus-type morphologies consisting of styrene and PFO. When the ternary mixtures of styrene/PFO/aqueous SDS solution are polymerized at 80°C, subsequent SEM observations indicate that the hollow cup-type polystyrene particles with a single hole on the surface are fabricated by polymerization using the Janus emulsion droplets. The hole size decreases with increasing polymerization time. These results suggest that morphologies of emulsions of ternary mixtures of hydrocarbon oil, fluorocarbon oil, and aqueous SDS solution contribute to those of polymer particles fabricated by the radical polymerization. Submicron capsules containing aqueous solutions of a fluorescent material are prepared through the hollow cup-type particles.

All-atom molecular dynamics analysis of kinetic and structural properties of ionic micellar solutions

All-atom molecular dynamics simulation results regarding aqueous sodium dodecyl sulfate (SDS) solutions have been presented. Both salt-free solutions with different SDS concentrations and those containing calcium chloride additives have been studied. The simulation has shown that surface-active SDS ions form stable premicellar aggregates. The obtained molecular dynamics trajectories have been used to describe both the kinetic and structural properties of solutions containing SDS molecular aggregates and the properties of individual aggregates. Aggregation kinetics has been investigated, and the characteristic sizes of the aggregates have been calculated by different methods. It has been found that the size of a premicellar aggregate with aggregation number n = 16 in a salt-free solution virtually does not depend on surfactant concentration. Radial distribution functions (RDFs) of hydrogen and oxygen atoms of water molecules relative to the center of mass of an aggregate have no local maxima near the aggregate surface; i.e., the surface is incompletely wetted with water. Corresponding RDFs of carbon atoms have one, two or three maxima depending on the surfactant concentration and the serial number of a carbon atom in the hydrocarbon radical of the surface- active ion. The study of the potentials of mean force for the interaction of sodium and calcium ions with an aggregate having aggregation number n = 32 shows that only calcium ions can be strongly bound to such an aggregate.