Surfactant Sodium Dodecyl Sulfonate Research Articles

Surfactant assisted dispersion of graphene in aqueous solution using mixed surfactants

In this work, graphene is initially dispersed in surfactant sodium dodecyl sulfonate (SDBS) in an aqueous solution. Sonication followed by centrifugation is the process used to disperse the graphene in an aqueous solution with the aid of SDBS. The concentration of graphene is determined using UV–Vis-NIR spectroscopy. A higher concentration of graphene is achieved just above the critical micelle concentration of SDBS in an aqueous solution. To further improve the concentration of graphene in an aqueous solution of SDBS, a second surfactant polyvinyl pyrrolidone (PVP) is used. The mixed surfactant strategy has increased the concentration of graphene in an aqueous solution by ∼ 400% as compared to SDBS aided dispersion of graphene in an aqueous solution. Atomic force microscopy (AFM) observations reveal the few-layer dispersion of graphene in an aqueous solution with the aid of mixed surfactants; while SDBS assisted dispersion of graphene in an aqueous solution shows the few layers to 10 s of layers of graphene nanosheets.

Improve the energy efficiency: Effects of additives on longtime zinc electrowinning

In this paper, the theoretical energy consumption required in the zinc electrowinning process was analyzed. The theoretical energy consumption is only a half of the energy consumption in industrial production. To save energy of the production process, we studied five kinds of additives with the industrial electrolyte in the longtime zinc electrowinning process. The results indicated that the presence of non-ionic compound (thiourea) or anionic surfactant (sodium dodecyl sulfonate or sodium dodecylbenzene sulfonate) adversely affected the energy consumption and current efficiency. However, an improvement in energy consumption was observed with the addition of cetyltrimethylammonium bromide. Our results should be helpful for the production of zinc electrowinning.

A facile strategy towards developing amphiphobic polysulfone membrane with double Re-entrant structure for membrane distillation

Membrane surface wetting and fouling are still crucial issues in many separation processes such as membrane distillation (MD), especially when oil-contained feed solution was treated. To solve that problem, a facile synthesis strategy for amphiphobic polymeric membrane was successfully proposed in the current work. Via traditional non-solvent induced phase separation (NIPS) and subsequent sol-gel process, double re-entrant structure was ingeniously constructed; that is, the first level re-entrant structure was supplied by the bicontinuous inter-connected porous structure obtained through optimized phase separation parameters and the second level re-entrant structure was offered by the spherical and dimensionally different silicon dioxide (SiO2) nanoparticles which were spontaneously generated during sol-gel process. After cooperating with the fluorine-contained chemical coating, the resultant polysulfone (PSf) membrane with double re-entrant structure exhibited excellent and stable repellency performance to both water and organic liquid, even showing high hexadecane contact angle of 121° and hexane of 67°. Compared with solely hydrophobic membrane, the as-fabricated amphiphobic PSf membrane achieved long-term stable vapor flux and salt rejection in MD process even with the presence of surfactant sodium dodecyl sulfonate (SDS).

Modulation of Antimicrobial Peptide Conformation and Aggregation by Terminal Lipidation and Surfactants.

The function and properties of peptide-based materials depend not only on the amino acid sequence but also on the molecular conformations. In this paper, we chose a series of peptides Gm(XXKK)nX-NH2 (m = 0, 3; n = 2, 3; X = I, L, and V) as the model molecules and studied the conformation regulation through N-terminus lipidation and their formulation with surfactants. The structural and morphological transition of peptide self-assemblies have also been investigated via transmission electron microscopy, atomic force microscopy, circular dichroism spectroscopy, and small-angle neutron scattering. With the terminal alkylation, the molecular conformation changed from random coil to β-sheet or α-helix. The antimicrobial activities of alkylated peptide were different. C16-G3(IIKK)3I-NH2 showed antimicrobial activity against Streptococcus mutans, while C16-(IIKK)2I-NH2 and C16-G3(IIKK)2I-NH2 did not kill the bacteria. The surfactant sodium dodecyl sulfonate could rapidly induce the self-assemblies of alkylated peptides (C16-(IIKK)2I-NH2, C16-G3(IIKK)2I-NH2, C16-G3(VVKK)2V-NH2) from nanofibers to micelles, along with the conformation changing from β-sheet to α-helix. The cationic surfactant hexadecyl trimethyl ammonium bromide made the lipopeptide nanofibers thinner, and nonionic surfactant polyoxyethylene (23) lauryl ether (C12EO23) induced the nanofibers much more intensively. Both the activity and the conformation of the α-helical peptide could be modulated by lipidation. Then, the self-assembled morphologies of alkylated peptides could also be further regulated with surfactants through hydrophobic, electrostatic, and hydrogen-bonding interactions. These results provided useful strategies to regulate the molecular conformations in peptide-based material functionalization.

A Gibbs free energy minimization based model for liquid–liquid equilibrium calculation of a system containing oil, brine, and surfactant

Accurate and reliable phase equilibrium calculations of microemulsion systems are of great importance. This study deals with the thermodynamic modeling of Liquid–Liquid Equilibrium (LLE) of a system including oil (n-decane), brine (containing CaCl2 salt), and ionic surfactant (sodium dodecyl sulfonate). Two models of UNIQUAC and UNIQUAC + Debye–Hückel were used for thermodynamic calculations. The LLE experimental data were utilized to estimate the binary interaction parameters of UNIQUAC model and the adjustable parameter, b, of the Debye–Hückel model. The thermodynamic model calculates the microemulsion phase’s compositions by minimizing the Gibbs free energy of the LLE system using a combination of genetic algorithm and fmincon function in order to prevent local minima. The thermodynamic modeling results show an appropriate agreement with the experimental data. Accordingly, the presented model of this study can be used as a suitable method to investigate the liquid–liquid equilibrium of systems containing oil, water, and surfactant.

Preparation of novel mesoporous GdVO4: Eu3+ crystals by CTAB-SDS micellar-assisted hydrothermal method in wide pH range

Using cetyl trimethyl ammonium bromide (CTAB) and sodium dodecyl sulfonate (SDS) as a template, the novel mesoporous europium doped miro-/nano-crystalline gadolinium vanadate (GdVO4:Eu3+) crystals were controllably synthesized by a facile hydrothermal process over a wide adjustable pH range. The structure, morphology and luminescence properties of GdVO4:Eu3+ crystals were characterized and compared by X-ray power diffraction (XRD), scanning electron microscope (SEM) transmission electron microscopy (TEM), nitrogen absorption-desorption and photoluminescence spectroscopy (PL). The results revealed that the pH influenced the nucleation rate of GdVO4:Eu3+ crystals in the reaction solution, and the CTAB and SDS performed a pivotal function in the morphology of final products via forming micelles and transforming growth direction. When the reaction solution was pH = 14, the cationic surfactant CTAB and anionic surfactant SDS were successively added, and the finally obtained phase-pure tetragonal GdVO4:Eu3+ crystals exhibited a mesoporous structure with a BET surface area of 11.41 m2∕g and the average nanocrystalline size in the range of 40–60 nm. Additionally, the mesoporous GdVO4:Eu3+ crystals showed the strongest luminescence intensity among all the samples with different morphologies.

Membrane Filtration of Anionic Surfactant Stabilized Emulsions: Effect of Ionic Strength on Fouling and Droplet Adhesion

Membranes hold great potential to be used for the successful treatment of oily waste water, but membrane fouling leads to substantial decreases in performance. Here we study the impact of ionic strength on membrane fouling from an emulsion stabilized by the anionic surfactant sodium dodecyl sulfonate (SDS). For this we use a unique combinatorial approach where droplet adhesion to a cellulose surface in a flow cell is compared to membrane fouling (flux decline) on a cellulose membrane. In the initial membrane fouling stages droplet adhesion dominates. While the flow cell demonstrates a high number of droplets adhering especially at high ionic strengths (100 mM NaCl), the strongest flux decline is observed at intermediate (10 mM NaCl) ionic strength. This suggests that the fouling mechanism must be different, with pore blocking expecting to dominate at intermediate ionic strength. At the later fouling stages the porosity of the cake layer plays a key role in the flux reduction. At low ionic strength, oil droplets repel each other strongly and an open, more permeable, cake layer is formed. However at higher ionic strength, a screening of charge interactions leads to a lower porosity and thereby a lower flux. This leads to a clear trend: with a higher ionic strength a higher flux decline is observed. Flux recovery is high at all ionic strengths, in line with the observation in the flow cell that oil droplets can easily be sheared of a cellulose surface at all ionic strengths. This work thus highlights the critical effect of the ionic strength on membrane fouling by anionically stabilized emulsions. Moreover it shows how the use of an optical flow cell can provide key insights to help explain observations in more standard membrane fouling experiments.

Effects of addition of short-chain alcohol solvents on micellization and thermodynamic properties of anionic surfactants sodium dodecyl sulfate and sodium dodecyl sulfonate in aqueous solutions

Micellar and thermodynamic properties of anionic surfactants sodium dodecyl sulfate (SDS) and sodium dodecyl sulfonate (SDSn) in aqueous solutions of 5 wt% short-chain alcohols methanol, ethanol, and 1-butanol were investigated by experimental electrical conductivities, densities and sound velocities at 298.15 K. It was found that methanol behaves like a cosolvent and increases the critical micelle concentration (CMC) of both surfactants in aqueous solutions. However, the other investigated alkanols act as a cosurfactant and decrease the CMC by their presence. The values of the degree of counterion association on the micelles of both surfactants in aqueous methanol solution are same as those in pure water, and they decrease with increasing the alkyl chain length of alcohol. Furthermore, the values of the apparent molar volume and isentropic compressibility of the monomeric and micellar forms of the investigated surfactants were obtained from the experimental density and sound velocity data. It was found that the values of the apparent molar properties of both micellar and monomeric forms of the studied surfactants increase by increasing the alkyl chain of the alcohols.

Interfacial molecular array behaviors of mixed surfactant systems based on sodium laurylglutamate and the effect on the foam properties

ABSTRACTThe foam properties of mixtures of an eco-friendly amino-acid derived surfactant sodium lauroylglutamate (LGS) interacting with cationic surfactant dodecyl trimethyl ammonium bromide (DTAB), nonionic surfactant laurel alkanolamide (LAA) and anionic surfactant sodium dodecyl sulfonate (SDS), were investigated, respectively. It was amazing that the three investigated binary-mixed systems all showed obviously synergism effect on foaming, though LGS/DTAB catanionic mixture showed remarkable synergistic effect with no surprise. The equilibrium and dynamic surface activity, along with the interfacial molecular array behaviors of binary-mixed systems with different molar ratios at air/water surface were also studied. Moreover, the theoretical simulation was employed to investigate how the interfacial behaviors of surfactants at air/water surface affected the foam properties. The study might provide the meaningful guidance for utilizing the LGS-based systems, especially in constructing eco-friendly foam systems in the application areas of cosmetics, medicine and detergent.

Synthesis and properties evaluation of sulfobetaine surfactant with double hydroxyl

A series of sulfobetaine surfactants {N-[(3-alkoxy-2-hydroxyl)propoxy] ethyl-N,N-dimethyl-N-(2-hydroxyl)propyl sulfonate} ammonium chloride were synthesized with raw materials containing linear saturated alcohol, N,N-dimethylethanolamine, sodium 3-chloro-2-hydroxyl propane sulfonic acid and epichlorohydrin. The molecule structures of sulfobetaine surfactants were characterized by FTIR, 1HNMR and elemental analysis. Surface tension measurements can provide us information about the surface tension at the CMC (γCMC), pC20, Γmax and Amin. The pC20 values of sulfobetaine surfactants increase with the hydrophobic chain length increasing. Amin values of the surfactants decrease with increasing hydrophobic chain length from 10 to 14. The critical micelle concentration (CMC) and surface tension (γCMC) values of the sulfobetaine surfactants decrease with increasing hydrophobic chain length from 10 to 16. The lipophilicity of surfactant was enhanced with the increase of the carbon chain, however, the ability of anti-hard water was weakened. The minimum oil/water interfacial tension of four kinds of sulfobetaine surfactants is 10−2–10−3 mN/m magnitude, which indicates that the synthesized bis-hydroxy sulfobetaine surfactants have a great ability to reduce interfacial tension in the surfactant flooding system. The surface tension (γCMC) values of synthesized surfactants were lower compared with conventional anionic surfactant sodium dodecyl sulfonate.

Wettability Modification of Lignite by Adsorption of Dodecyl Based Surfactants for Inhibition of Moisture Re‐adsorption

AbstractIn order to restrain moisture re‐adsorption of dried lignite, a series of dodecyl based surfactants with various hydrophilic heads including dodecyltrimethylammonium bromide (DTAB), sodium dodecyl sulfonate (SDS), dodecyl nonaethoxyl ether (C12EO9) and a gemini surfactant (G12‐2‐12) were used to adsorb on lignite surface for wettability modification. The adsorption isotherms and zeta potential were determined to study the adsorption process. Lagergren‐first‐order and pseudo‐second‐order kinetics models were used to simulate the adsorption kinetics. The modified lignite was characterized by FTIR spectroscopy, and the wettability of it was evaluated by the wetting heat and moisture re‐adsorption ratio. The results indicate that hydrophilic heads of surfactants play an important role in adsorption mechanisms and structures of their adsorption layers on lignite surface, which are responsible for wettability alteration. Four surfactants produce different effects on restraining moisture re‐adsorption of lignite: the effect of cationic surfactants is better and worse for anionic surfactant SDS, while the non‐ionic surfactant C12EO9 shows intermediate behavior. But with the formation of double‐layer adsorption, hydrophilic headgroups of surfactant face outward, which causes hydrophilicity of lignite to rise again. Combining adsorption situations and wettability modification effects, the relationship between molecular orientation of four surfactants on a lignite surface and wettability reversal of lignite are discussed.

Surfactant assisted solvothermal synthesis of LiFePO4 nanorods for lithium-ion batteries

Well-shaped and uniformly dispersed LiFePO4 nanorods with a length of 400–500 nm and a diameter of about 100 nm, are obtained with participation of a proper amount of anion surfactant sodium dodecyl sulfonate (SDS) without any further heating as a post-treatment. The surfactant acts as a self-assembling supermolecular template, which stimulated the crystallization of LiFePO4 and directed the nanoparticles growing into nanorods between bilayers of surfactant (BOS). LiFePO4 nanorods with the reducing crystal size along the b axis shorten the diffusion distance of Li+ extraction/insertion, and thus improve the electrochemical properties of LiFePO4 nanorods. Such prepared LiFePO4 nanorods exhibited excellent specific capacity and high rate capability with discharge capacity of 151 mAh/g, 122 mAh/g and 95 mAh/g at 0.1 C, 1 C and 5 C, respectively. Such excellent performance of LiFePO4 nanorods is supposed to be ascribed to the fast Li+ diffusion velocity from reduced crystal size along the b axis and the well electrochemical conductivity. The structure, morphology and electrochemical performance of the samples were characterized by XRD, FE-SEM, HRTEM, charge/discharge tests, and EIS (electrochemical impedance spectra).

Investigation on the co-modification process of montmorillonite by anionic and cationic surfactants

To study how anionic surfactant sodium dodecyl sulfonate (SDS) and cationic surfactant cetyltrimethylammonium chloride (CTAC) enter the interlayer spaces of montmorillonite, montmorillonite, CTAC and SDS were exchanged consecutively and simultaneously. Three parameters were investigated: reaction times, surfactants contents and addition sequences. The results of XRD, thermal analysis and sulfur analysis stated that SDS could not intercalate into montmorillonite interlayer space alone. However, it can enter the interlayer space of montmorillonite in the presence of CTAC. The addition sequences of cationic and anionic surfactants affect the d-value and thermal stability of anionic-cationic montmorillonite. The data obtained from elemental analysis clarified the steps of this multistep reaction sequence and a mechanistic scheme has been proposed: a portion of cationic surfactants intercalate into the interlayer spaces of montmorillonite by cation exchange firstly, and then the anionic surfactant enter the interlayer spaces of montmorillonite by the synergistic effect with cationic surfactants. Molecular simulation indicated the arrangement of cationic and anionic surfactants intercalated into montmorillonite interlayer space.

Synthesis of oligomer betaine surfactant (DDTPA) and rheological properties of wormlike micellar solution system

Novel oligomer betaine surfactant penta sodium N, N′, N″- dodecyl diethylene triamine pentaacetic acid (DDTPA) with three dodecyls, five carboxylic acid groups and three quaternary ammonium were synthesized through two steps in this paper. Rheological properties of mixed oligomer betaine surfactant DDTPA/anionic surfactant sodium dodecylsulfonate (SDS) solution systems were studied as functions of SDS concentration, inorganic salt KCl dosage and temperature. Stable and dynamic viscoelastic measurements were carried out to investigate the characters of wormlike micelles formed in certain condition. In the 2.5wt% DDTPA, 4wt% KCl and SDS system, the optimal SDS concentration is 1.2wt%, at which the viscosity reaches a maximum. Interestingly, with adding inorganic salt KCl to mixed surfactant solution(2.5wt% DDTPA, 1.5wt% SDS), the water-like fluid turns into gel-like viscoelastic wormlike micellar solution immediately owing to the screening electrostatic repulsion among the surfactant charged groups by counterions. When KCl concentration is 3wt%, the micellar solution obtains a peak value in viscosity. For the system with 2.5wt% DDTPA, 1.5wt% SDS, 4wt% KCl, the micellar contour length decreases with increasing temperature, leading to an exponential decrease in the values of η0 and τR. This work provides a clear understanding of the profound relationship between surfactant wormlike micellar characteristic and the rheological properties. The dynamic viscoelastic behavior of wormlike micelles usually fits for the Maxwell mode in low oscillation frequency region, but in medium and high frequency region it fits for t the modified Maxwell model.

Synthesis of large-scale, monodisperse latex particles via one-step emulsion polymerization through in situ charge neutralization

Abstract Monodisperse sub −200 nm polystyrene nanoparticles were synthesized by a facile one-step emulsion polymerization technology using sodium dodecyl sulfonate (SDS) and 2, 2′- azobis (2-methylpropionamide) dihydrochloride (AIBA) as the surfactant and initiator, respectively. The in situ neutralization between negatively charged surfactant SDS and positively charged AIBA was used to control the primary particle (or swollen micelle) volume and the extent of the particle coagulation. As the oligomeric radicals with cationic AIBA chain ends were captured by anionic swollen micelles, the electrostatic stability of swollen micelles gradually reduced, further promoting the primary particle coagulation. As a result, the initial particle number decreased with the addition of AIBA. The earlier primary particle coagulation not only enlarged the particle size, but also narrowed the particle size distribution of final the latex particles.

The interconversion between gold nanostars and gold nanodendrites controlled via temperature and the concentration of sodium dodecyl sulfonate

Gold nanostars and gold nanodendrites were readily synthesized by the reduction of HAuCl4 with ascorbic acid in aqueous mixed solutions of the cationic surfactant decane-1,10-bis(methylpyrrolidinium bromide) ([mpy-C10-mpy]Br2) and the anionic surfactant sodium dodecyl sulfonate (SDS). The interconversion of morphologies between gold nanostars and gold nanodendrites can be achieved by changing the reaction temperature under the otherwise identical conditions, which is seldom reported. Due to the electrostatic interaction, the introduction of SDS brought the dramatic impact to the formation process and the final morphologies of the gold nanostructures. Both of the hierarchical structures were found to yield large surface-enhanced Raman scattering (SERS) enhancement factors for rhodamine 6G (R6G) and the aspect ratio is a key factor for the enhancement.

Influence of montmorillonites exchange capacity on the basal spacing of cation–anion organo-montmorillonites

With cationic and anionic surfactants cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfonate (SDS) as modifiers, Ca-montmorillonites (Ca-Mt), artificial Na-montmorillonites (R-Na-Mt) and natural Na-montmorillonites (Na-Mt) with different cation exchange capacity (CEC) were modified by solution intercalation method, respectively. Then cation–anion organo-montmorillonites (OMt) were prepared. The influence of CEC on the basal spacing of cation–anion OMt and the influence mechanism were discussed by X-ray diffraction (XRD) and zeta potential testing. The results indicate that the basal spacing of cation–anion OMt is related to CEC. For the same type montmorillonites, the basal spacing of cation–anion OMt decreases with the increase of CEC and it is easier to get cation–anion OMt with greater basal spacing when CEC is lower. Moreover, the CEC of Na-Mt has the greatest influence on the basal spacing of cation–anion OMt.

Micellization properties and related thermodynamic parameters of aqueous sodium dodecyl sulfate and sodium dodecyl sulfonate solutions in the presence of 1-propanol

Effects of 1-propanol (1P) addition on the micellar and thermodynamic parameters of aqueous solutions of anionic surfactants sodium dodecyl sulfate (SDS) and sodium dodecyl sulfonate (SDSn) was investigated by experimentally measured electrical conductivities, densities and sound velocities at 298.15K. The values of the critical micelle concentration (CMC) of both surfactants in the investigated mixed aquo-1P solvents (wt% 1P 2.5, 5, 7.5 and 10) are smaller than those in pure water and the CMC decreases with increasing 1P concentration in solution to a minimum at (w/w) % 1P=5 and then increases. However the values of the counterion condensation on the micelle decrease with an increment in the amount of 1P. Furthermore the values of the apparent molar volume and isentropic compressibility of the monomeric and micellar forms of the investigated surfactants were obtained from the experimental density and sound velocity data. It was found that, although the values of the apparent molar properties of micellar form of surfactants increase by increasing the organic solvent content, the values of the apparent molar volume of the monomeric form of the surfactants decrease with increasing concentration of 1P.

Shape-controlled Synthesis of Activated Bio-chars by Surfactant-templated Ionothermal Carbonization in Acidic Ionic Liquid and Activation with Carbon Dioxide

Shape-controlled bio-chars were synthesized in two steps: (i) ionothermal carbonization of biomass (e.g., glucose, cellulose, lignin, and bamboo) at low temperatures (150 to 180 °C) in an acidic ionic liquid (IL), and (ii) subsequent activation with carbon dioxide at higher temperature (500 °C). Acidic IL was used as both the medium and catalyst for advanced carbon materials production. During the first step the primary structures of spherical particles were obtained. The surfactants sodium dodecyl sulfonate (SDS), ethylene glycol (EG), and sodium oleate (SO) were also used to modify the surface morphology of bio-chars and activated bio-chars. After the second step, the primary structures of bio-chars were still preserved or improved. The Brunauer-Emmett-Teller surface area and the pore diameter of activated bio-chars were 289 to 469 m2/g and 3.5 to 3.6 nm, respectively. Scanning electron microscope and transmission electron microscope images show that after modification of bio-chars with SDS, EG, and SO, activated bio-char particles agglomerated into rod-like (~200 nm diameter), nano-membrane (~70 nm thickness), and spherical (~200 nm) morphologies, respectively. The morphology of activated bio-chars was easily controlled during the synthesis, which is important for the exploitation of their peculiar properties and unique applications.

Controlling the growth of porphyrin based nanostructures for tuning third-order NLO properties

A series of porphyrin nanospindles with controlled long axis length distributions of 330, 550, 800 nm, and 4 μm have been successfully fabricated via hierarchical self-assembly of cationic porphyrin (H₆TPyP)(4+) with the help of anionic surfactant sodium dodecyl sulfonate (SDS) due to the effective electrostatic interaction. These newly fabricated nanostructures are characterized by TEM and SEM techniques, powder X-ray diffraction analysis, electronic absorption spectroscopy, and confocal laser scanning microscopy (CLSM). The Z-scan technique with a laser duration of 5 ns at the wavelength of 532 nm reveals unreported size-dependent third-order NLO switching properties: the nonlinear absorption changes from saturation absorption to reversed saturation absorption and the nonlinear refraction from self-defocus to self-focus due to the change of the dominant scattering effect, from Rayleigh scattering for nanostructures with a smaller size than the wavelength of laser light, to Mie scattering for nanostructures with a larger size than the laser wavelength. This result is useful for the development of organic nanostructures with desired NLO properties, in particular the optical limiting properties.