Binary Surfactant Systems Research Articles

Solubilization of polycyclic aromatic hydrocarbons by novel ester-bonded Gemini prolinol-based surfactant and its binary mixtures with conventional surfactants

Aqueous interactions of a novel ester-bonded Gemini prolinol-based surfactant, 2,2′-((adipoylbis(oxy))bis(methylene))bis(1-dodecyl-1-methylpyrrolidin-1-ium) bromide C12-6-C12PB, with dodecyl sodium sulfate (SDS), dodecyl trimethyl ammonium bromide (DTAB), tetradecyl trimethyl ammonium bromide (TTAB), or cetyltrimethyl ammonium bromide (CTAB) were studied using conductomeric measurement. The experimental critical micelle concentration (CMC) was lower than the ideal CMC, and the negative interaction parameters indicate that there is a synergistic interaction between the surfactants in the binary solution. The solubilization capacities of single and binary surfactant systems towards polycyclic aromatic hydrocarbons (PAHs) (i.e., naphthalene, anthracene, and pyrene) were evaluated and are discussed in terms of the molar solubilization ratio (MSR), micelle-water partition coefficient (Km), and free energy of solubilization (). C12-6-C12PB and SDS respectively had the minimum and maximum MSR when presented individually in the solution. The MSR values in the binary system are greater than those in the single surfactant system, and this indicates that synergism in a mixed system enhances PAH solubility. With a molar ratio of 0.7:0.3, C12-6-C12PB/SDS had a relatively greater solubilization capacity for PAHs because of large aggregates. The negative value of indicates the spontaneity of the solubilization process.

Influence of concentration ratio on emulsifying properties of Quillaja saponin - protein or lecithin mixed systems

The concentration ratio of binary surfactant systems can alter the interfacial layer properties, and consequently affect emulsion stability. To study the effect of varying concentration ratios (r, % w/w) of interfaces containing Quillaja saponins and other naturally occurring food-grade surfactants on their emulsifying properties, we evaluated particle size, ζ-potential, and appearance of 10% oil-in-water emulsions (pH 7) stabilized by Quillaja saponin - protein or Quillaja saponin - lecithin mixtures. Quillaja saponin - Na-caseinate mixtures (r = 0.3:0.2, 0.2:0.3, and 0.1:0.4) formed small emulsion droplets (d43: 0.2 – 0.3 μm), whereas at r = 0.4:0.1, the emulsions contained micron-sized droplets (d43: 1.217 ± 0.558 μm). Emulsions formed by Quillaja saponin - pea protein mixtures flocculated at r = 0.3:2.0, 0.2:3.0, and 0.1:4.0. In contrast, Quillaja saponin - rapeseed lecithin or egg lecithin mixtures were able to generate small emulsion droplets (d43: 0.2 – 0.5 μm) at all tested concentration ratios. The formation of stable emulsions using binary mixtures of naturally occurring emulsifiers was more dependent on the concentration ratio of the proteins than lecithins, indicating that the interfacial behavior of Quillaja saponins is more sensitive to the presence of proteins. This was attributed to attractive molecular interactions yielding complexes at interfaces and/or in the continuous phase. This study shows that food-grade binary surfactant mixtures can be used to form stable emulsions with properties being tunable by altering the mixing ratios between surfactants.

Surface properties and doxorubicin delivery in mixed systems comprising a natural rosin-based ester tertiary amine and an anionic surfactant

A rosin-based ester tertiary amine salt (RETAS) cationic surfactant was obtained using natural rosin as raw material. GC-MS of RETAS was detailed analyzed. The pH-responsive mechanism of rosin-based ester tertiary amine (RETA) and RETAS was confirmed by applying theoretical calculations about electrostatic potential maps of RETA and RETAS cation using Gaussian software. Mixed system surfactants were obtained by blending RETAS cationic surfactant with sodium dodecyl benzene sulfonate (SDBS) anionic surfactant. The binary mixed surfactant systems of RETAS and SDBS had obvious synergistic effect. The γcmc and CMC were 39.40 mN/m and 0.56 mmol/L at the optimum molar fraction of RETAS (α) = 0.6, respectively. The stability time of emulsion with the optimum mixed system as emulsifier increased to 309 s at α = 0.6. The emulsifying capacity of RETAS was much better than that of RETA. RETAS had pH-responsive targeted release and the optimum mixed system showed a relatively sustained drug release by using doxorubicin (DOX) as a model drug. These results indicate that RETAS surfactant and mixed system surfactant are both promising for applications in drug delivery and emulsification.

Research of Binary Surfactant Mixtures Based on N-Lauroyl Sarcosinate

Abstract Surface properties of binary surfactant systems of N-lauroyl sarcosinate (LS) with fatty alcohol polyoxyethylene ether (AEO9), dodecyl trimethyl ammonium chloride (DTAC) and dodecyl dimethyl betaine (BS-12) have been investigated in aqueous NaCl (0.1 mol · L−1) solution at (298 ± 0.1) K, respectively. Synergistic parameters of the two components in both mixed micelles and mixed adsorption layers were obtained by calculations. Furthermore, we applied the regular solution theory on the mixed systems when synergism in mixed micelle formation, surface tension reduction efficiency and surface tension effectiveness was researched. The results show that there are synergistic effects in the mixed systems, the surface performances of the mixtures are significantly better than that of any single component in the mixed systems. The result coincides with the relevant theories of the ability of mixed micelle formation, surface tension reduction efficiency and surface tension reduction effectiveness.

Solubility Enhancement of Polycyclic Aromatic Hydrocarbons by an Eco-Friendly Ester-Linked Gemini Surfactant and its Mixtures with Conventional Surfactants

AbstractThe present study deals with the solubility enhancement of the two polycyclic aromatic hydrocarbons (PAHs) anthracene and pyrene in the aqueous micellar system of the cationic ester-containing cleavable gemini surfactant ethane-1,2-diyl-bis(N,N-dimethyl-N-tetradecylammoniumacetoxy) dichloride (14-E2-14 = C14H29(CH3)2N+(CH2COOCH2)2N+(CH3)2C14H29 · 2Cl−)), and its equimolar binary mixtures with some typical conventional cationic, anionic and non-ionic surfactants. The surface tension and conductivity measurements were used to evaluate the physicochemical parameters such as the critical micelle concentration (CMC), the interaction parameter (βm) and Gibbs excess free energy of micellization (ΔGexm) of the systems. The extent of solubilization of the micellar systems towards PAHs has been quantified in terms of molar solublization ratio (MSR), micellar/water partition coefficient (ln Km) and the standard Gibbs free energy of solubilization (ΔGs0). Above the CMC, all studied single as well as binary gemini-conventional surfactant systems show an increase in solubilization of the PAHs. For pure systems, the MSR value of Brij 58 was found to be significantly higher than that of the other amphiphiles. Amongst the mixed surfactant systems, the solubility enhancement of anthracene is found to be maximum in the 14-E2-14 + SDS/SDBS system whereas the system14-E2-14 + Brij 58 shows a higher solubility for pyrene.

Synergism and aggregation behaviour in an aqueous binary mixture of cationic-zwitterionic surfactants: physico-chemical characterization with molecular simulation approach.

Aqueous interactions between a cationic surfactant benzyl dimethylhexadecylammonium chloride (BDHAC) and alkyldimethylammoniopropane sulfonates (CnDAPS) based three zwitterionic surfactants n = 10, 12, and 14 (abbreviated as C10DAPS, C12DAPS and C14DAPS, respectively) were studied using tensiometry, and fluorescence spectrophotometry techniques. The critical micelle concentration degree of synergism and various other parameters such as interaction parameter (β), activity coefficients (fm) and interfacial parameters such as surface pressure (πCMC), packing parameter (P), surface excess concentration (Γmax), surface tension at CMC (γCMC), and minimum area per molecule (Amin) were evaluated using the Regular Solution Theory (RST) of mixed systems. The results indicate a strong dependency on the mixed system and their composition. For the quantitative prediction, the molecular architecture of the surfactants in mixed systems and their synergistic interactions were investigated by computational simulation using Spartan'14 V1.1.8. The structural optimization results obtained were found to be in good agreement with the estimations made using RST. The reduction in surface tension indicates a certain efficiency in mixed micelle formation owing to electrostatic attraction between the cationic and zwitterionic surfactants. In addition, the binary surfactant systems evaluated by Maeda's approach infer the mixed micelles are thermodynamically stable. The aggregation number (Nagg) appeared to be larger at the composition point where the efficiency of mixed micelle formation is greatest. The strength of the interaction between BDHAC and CnDAPS followed the order: C14DAPS > C12DAPS > C10DAPS indicating a greater synergism at 0.25 molar ratio of zwitterionic surfactants to cationic surfactants in the aqueous solution at 303.15 K.

Self‐Assembly Behaviors of Anionic–Cationic Binary Surfactant Systems in Poly(ethylene glycol) 200

AbstractThe self‐assembly behaviors of mixtures of sodium bis(2‐ethylhexyl) sulfosuccinate (AOT) and didodecyl dimethylammonium bromide (DDAB) in polyethylene glycol 200 (PEG 200) and in water were investigated by surface tension, conductivity, steady‐state fluorescence and dynamic light scattering (DLS) methods. The results show that the oppositely charged binary surfactant system can form micelles in PEG 200; the critical micellization concentration (CMC) decreases for the binary system versus those of either surfactant alone. Although there is no charge screening in the PEG 200 system, the CMC values significantly increase and the system does not precipitate or show turbidity at any proportion of AOT to DDAB, while a multiphase composition gap exists in water due to the strong electrostatic attraction. It is speculated that the weak polarity of PEG 200, the decreased solvophobic interaction between the alkyl chain and PEG 200, and the loose structure of the resulting micelles might explain the experimental phenomena. Observed from the values of the interaction parameter, it is found that there are a strong attractive interaction and a synergistic effect between AOT and DDAB in aqueous solution, in comparison, the synergy between them in PEG 200 is very weak.

Hexadecyltrimethylammonium bromide (CTA-Br) and 1-butyl-3-methylimidazolium tetrafluoroborate (bmim-BF4) in aqueous solution: An ephemeral binary system

HypothesisMixtures of the cationic surfactant hexadecyltrimethylammonium bromide (CTA-Br) and the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (bmim-BF4) in aqueous solutions are expected to behave as typical binary cationic surfactant system taking into account the surface activity displayed by the ionic liquid, instead of considering the IL as a water cosolvent. ExperimentsSurface tension and conductivity measurements have been conducted as a function of the total concentration of the mixtures at different surfactant mole fraction (αCTA-Br) to investigate the surface active properties. FindingsTurbidity immediately appearing when the compounds are mixed in water suggests the spontaneous formation of the low soluble compound hexadecyltrimethylammonium tetrafluoroborate (CTA-BF4), together with the salt formed by the respective counterions bmim+and Br− in solution. For αCTA-Br≠0.5, furthermore of the mentioned compounds, the spare bmim-BF4 (for αCTA-Br<0.5) or CTA-Br (for αCTA-Br>0.5), are also present in the aqueous solution. Systems containing excess of bmim-BF4 show a low critical aggregate concentration (cac), but an unexpected high surface tension at cac (γcac≈53–56mN/m), as pure CTA-BF4. For systems containing excess of CTA-Br, cac increases but γcac decreases up to 36mN/m. Mixtures of pure CTA-BF4 and bmim-BF4 or CTA-Br behave as typical binary surfactant systems.

Synthesis of mesoporous silica materials (MCM‐41) using silica fume as the silica source in a binary surfactant system assisted by post‐hydrothermal treatment and its Pb2+ removal properties

AbstractMesoporous silica materials (MCM‐41) were successfully prepared by substituting silica fume for silicate in different surfactant systems. The effects of binary surfactant systems and post‐hydrothermal treatment on the morphology and structural properties of MCM‐41 were investigated based on X‐ray diffraction (XRD), N2 sorption/desorption, and transmission electron microscopy analyses (TEM). The results confirmed that polyethylene glycol (PEG‐6000) is an effective additive template in a binary surfactant system for the synthesis of mesoporous silica materials. Meanwhile, the hydrothermal stability of the mesoporous silica materials can be improved by post‐hydrothermal treatment and the optimal experimental parameters are a temperature of 140 °C and a treatment time of 48 h. The formation of high‐quality MCM‐41 is based on the balance between the ordered assembly of the inorganic anionic species and cationic surfactant, in accordance with the electrostatic interactions and hydrogen bonds between PEG‐6000 and the inorganic species. Meanwhile, Pb(II) removal from aqueous solution has also been examined using MCM‐41 as an adsorbent. The results of adsorption showed that the as‐synthesized MCM‐41 demonstrated a high capacity of Pb2+.

Influence of heat on miscibility of Quillaja saponins in mixtures with a co-surfactant

Thermal treatment of mixed surfactant systems can have a major impact on their phase behavior through modified interactions between the surfactants. In this study, we investigated the miscibility behavior of aqueous binary surfactant systems composed of Quillaja saponin extract and sodium caseinate, pea protein, rapeseed lecithin, or egg lecithin at different concentration ratios (0–5% w/v) at pH3, 5, and 7 upon heat treatment (25–75°C). The results revealed that the heat-treated Quillaja saponin–sodium caseinate mixtures at pH7 remained miscible when the ratio of Quillaja saponins was equal or higher to the ratio of caseinate, otherwise the mixtures flocculated due to increased hydrophobic interactions. At pH3, the aggregation of Quillaja saponin–sodium caseinate structures was intensified by heating mainly through self-association of casein molecules. In Quillaja saponin–pea protein mixtures as well as in pure pea protein samples heating led to weakening of the gel structures at all tested pH values. In contrast, heating did not affect Quillaja saponin–rapeseed lecithin mixtures, which stayed miscible independent of pH due to electrostatic repulsive forces. Furthermore, the flocculated (pH5, 7) or aggregated (pH3) Quillaja saponin–egg lecithin mixtures were only slightly affected by heating. These results are important for understanding the interactions of binary surfactant systems when subjected to heating, which is a common processing step in many food applications.

Core Freezing and Size Segregation in Surfactant Core-Shell Micelles.

Nonionic surfactants containing poly(ethylene oxide) are chemically simple and biocompatible and form core-shell micelles at a wide range of conditions. For those reasons, they and their aggregates have been widely investigated. Recently, irregularities that were observed in the low-temperature behavior of surfactants of the kind [CH3(CH2)(n)O(CH2CH2O)(m)H], (abbreviated CnEm) were assigned to a freezing-melting phase transition in the micellar core. In this work we expand the focus from the case of single component systems to binary surfactant systems at temperatures between 1 and 15 °C. By applying small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), and density measurements in pure C18E20 and C18E100 solutions and their mixtures, we show that core freezing/melting is also present in mixtures. Additionally, comparing SAXS data obtained from the mixture with those from the single components, it was possible to demonstrate that the phase transition leads to a reversible segregation of the surfactants from mixed micelles to distinct kinds of micelles of the two components.

Self-Assembly of Calcium Carbonate Nanoparticles in Water and Hydrophobic Solvents

The self-assembly of Ca2+ and CO32– ions into nanoparticles in water and hydrophobic solvents is investigated using molecular dynamics (MD) computer simulation. A new three-stage particle assembly procedure is used which relaxes the structure of the nanoparticle toward a lower energy state. In hydrophobic solvent the bare particle is essentially spherical whereas in water it is ellipsoidally shaped. With surfactant stabilizer the nanoparticles typically exhibit nonspherical cores in model hydrophobic solvents. Binary surfactant systems exhibit synergistic effects where for example a salicylate-sulfonate combination forms a cage which promotes a compact core. Synergistic effects on the shape of the particle were also observed in a hydrophobic solvent for surfactant-stabilized systems with trace water as a third component. The simulations show that rather than being a rigid structure the carbonate core shape and stabilizing shell coverage are sensitive to solvent, surfactant, and small polar molecules which act as cosurfactants.

Strong cooperative effect of oppositely charged surfactant mixtures on their adsorption and packing at the air-water interface and interfacial water structure.

Remarkable adsorption enhancement and packing of dilute mixtures of water-soluble oppositely-charged surfactants, sodium dodecyl sulfate (SDS) and dodecyl amine hydrochloride (DAH), at the air-water interface were observed by using sum frequency generation spectroscopy and tensiometry. The interfacial water structure was also observed to be significantly influenced by the SDS-DAH mixtures, differently from the synergy of the single surfactants. Most strikingly, the obtained spectroscopic evidence suggests that the interfacial hydrophobic alkyl chains of the binary mixtures assemble differently from those of single surfactants. This study highlights the significance of the cooperative interaction between the headgroups of oppositely charged binary surfactant systems and subsequently provides some insightful observations about the molecular structure of the air-aqueous interfacial water molecules and, more importantly, about the packing nature of the surfactant hydrophobic chains of dilute SDS-DAH mixtures of concentration below 1% of the CMC.

Influence of surfactant hydrophobic segment length on the thermodynamic parameters of binary mixed micelles of homologues polysorbates and Triton X-100

It is important to find binary surfactant systems having synergistic interactions (negative value of the interaction parameter) since it means that a binary surfactant mixture composition exists in these systems, having lower critical micelle concentration value than more hydrophobic mixture component. In this work, influence of hydrophobic segment length of homologues Tweens in mixed micelles with Triton X-100 on the interaction parameter value (βij) and on the excess Gibbs energy (GE) was studied. Also, influence of temperature on the stability of investigated mixed micelles has been investigated (298.15–328.15K). The critical micelle concentration values of pure surfactants and their binary mixtures were determined spectrofluorimetrically using pyrene as a probe molecule. It was found for every investigated temperature that increase in length of saturated aliphatic side chain of a polysorbate increases the stability of investigated mixed micelles (βij<0 and GE<0) compared to the ideal mixed micelles.Presence of the C9 double bond in oleic acid residue of Tween 80 reduces synergistic effect of this polysorbate compared to Tween 60 which contains hydrophobic segment with the same number of C atoms but without olefin bond.The excess free enthalpy below the 298.15K is determined with entropic contribution, but above 298.15K with enthalpic contribution.

Influence of Micellar Propinquity on Dynamics of Ce(IV)‐Catalyzed BZ Oscillatory Reaction under Stirred Conditions

ABSTRACTOscillating reactions often employed to mimic and understand complex dynamics in biological systems are known to be affected in aggregated host environments. The dynamic evolution of the oscillatory Belousov–Zhabotinsky (BZ) reaction upon addition of increasing amounts of anionic (sodium dodecylbenzenesulfonate; SDBS), cationic (hexadecyltrimethylammonium bromide; CTAB), nonionic (polyoxyethylene(20) cetyl ether; Brij58), and binary mixtures (CTAB + Brij58 and SDBS + Brij58) of surfactants was monitored using potentiometry at 25 and 35°C under stirred batch conditions. The experimental results reveal that the oscillatory parameters of the Ce(IV)‐catalyzed BZ reaction are significantly altered depending on the concentration and nature of restricted micellar host environments. In the presence of ionic surfactants, it is proposed that the evolution of the oscillatory BZ system may be due to atypical proficiency (related to hydrophobic and electrostatic interactions) of such organized self‐assemblies to affect the reactivity by selectively confiscating some key reacting species. However, the response of the BZ system to nonionic Brij58 was attributed to the reaction among the alcoholic functional groups of the surfactant with some vital species of the BZ reaction. Moreover, the nonionic + ionic binary surfactant systems exhibited behaviors representative of both the constitutive single surfactant systems.

Mixed micellization of gemini and cationic surfactants: Physicochemical properties and solubilization of polycyclic aromatic hydrocarbons

The micellar and surface properties of single as well as equimolar binary mixed systems of some cationic gemini and monomeric ionic surfactants have been studied by conductivity, surface tension and fluorescence measurements at 300K. The critical micelle concentration (CMC), Γmax (maximum surface excess), Amin (minimum surface area per molecule), πcmc (surface pressure at the CMC) and thermodynamic parameters viz. standard Gibbs free energies of adsorption (ΔGads°), standard Gibbs free energies of micellization (ΔGm°) and minimum free energy of the surface (ΔGmin(s)) of gemini with cationic monomeric surfactants were also evaluated. The negative values of ΔGads° and ΔGm° indicate the spontaneity and stability of the mixed micelle. The experimental CMC values are less than the ideal CMC values, indicating negative deviation from ideal behavior for all the equimolar binary surfactant systems. Aggregation number (Nagg) and Stern–Volmer quenching constant (Ksv) have been evaluated by Fluorescence measurement. The solubilization capacities of selected single and equimolar binary surfactant systems toward polycyclic aromatic hydrocarbons (PAHs), i.e., naphthalene, anthracene and pyrene have been evaluated and discussed in terms of the molar solubilization ratio (MSR), the micelle-water partition coefficient (K(m)), the deviation ratio (R), and the free energy of solubilization (ΔGs°) of PAHs. The negative value of ΔGs° shows spontaneity of solubilization process.

One-pot synthesis of gold nanorods using binary surfactant systems with improved monodispersity, dimensional tunability and plasmon resonance scattering properties

A facile seedless growth method for high-yield synthesis of monodisperse gold nanorods using binary surfactant mixtures is reported for the first time. In comparison with other seedless methods, the present method enables the preparation of gold nanorods with much better monodispersity. Moreover, the present seedless growth method enables the preparation of not only thin gold nanorods but also thick gold nanorods which cannot be prepared by other reported seedless methods. Dark-field microscopy measurements of a single gold nanorod indicate that the thicker gold nanorod shows enhanced scattering properties.

Correction to Controlled Fabrication of Hexagonally Close-Packed Langmuir–Blodgett Silica Particulate Monolayers from Binary Surfactant and Solvent Systems

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionORIGINAL ARTICLEThis notice is a correctionCorrection to Controlled Fabrication of Hexagonally Close-Packed Langmuir–Blodgett Silica Particulate Monolayers from Binary Surfactant and Solvent SystemsYudi Guo, Dongyan Tang*, Yunchen Du, and Binbin LiuCite this: Langmuir 2013, 29, 42, 13121Publication Date (Web):October 7, 2013Publication History Published online7 October 2013Published inissue 22 October 2013https://doi.org/10.1021/la401876aCopyright © 2013 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views310Altmetric-Citations1LEARN 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 (634 KB) Get e-Alerts Get e-Alerts

Solubilization of polycyclic aromatic hydrocarbons by gemini–conventional mixed surfactant systems

The effects of mixed gemini–conventional surfactants on the aqueous solubility of polycyclic aromatic hydrocarbons (PAHs—naphthalene, anthracene, pyrene) were investigated. The critical micelle concentration (cmc) of the cationic gemini pentanediyl-1,5-bis(dimethylcetylammonium bromide) (G5) and its 1:1 mixtures with conventional surfactants cetyltrimethylammonium bromide (CTAB), sodium bis(2-ethylhexyl) sulfosuccinate (AOT) and polyoxyethylene (20) cetyl ether (Brij 58) were evaluated using the surface tension measurements. The maximum surface excess concentration at the air/water interface (Γmax), minimum area per head group (Amin), interaction parameters (βm, βσ) as well as other thermodynamic and micellar parameters were evaluated. Above cmc, for each of the single or binary system, the solubility of PAH in water is greatly enhanced in a linear fashion; the enhancement being more in the mixed surfactants. For the binary surfactant systems synergism in G5–CTAB, G5–Brij 58 and antagonism in G5–AOT are observed. The gemini–conventional mixed surfactant systems can solubilize PAHs synergistically due to the increase in molar solubilization ratio (MSR) and partition coefficient (Km) of the solute in the micellar phase.Results from this study could be exploited for the use of surfactant mixtures for environmental remediation as the mixed surfactants are anticipated to improve the performance of surfactant-enhanced remediation of soils and sediments contaminated by hydrophobic organic compounds by decreasing the applied surfactant level for the needed solubility of the PAHs in aqueous solutions.

Properties of Binary Surfactant Systems of a Cationic Ester-Containing Gemini Surfactant with Some Conventional Surfactants in Aqueous Solutions

Abstract Gemini surfactant, N,N′-bis(dimethyl ethyl dodecane)ethyl ether dibromide was synthesized and symbolized as II-12-EO2. The surface chemical properties and micelle behaviors of II-12-EO2 with poly (ethylene oxide) (PEO) lauryl ether (C12E6) and sodium dodecyl sulfate (SDS) were investigated in 0.1 mol · L−1 sodium bromide aqueous solution at 313 K using surface tension measurements and steady-state fluorescence spectroscopy. The critical micelle concentration (cmc) of II-12-EO2 is 1.99 × 10−4 mol · L−1 and the aggregation number is 23. The cmc values of the two binary systems with different molar fractions are all lower than those of pure constituent surfactants, and the aggregation numbers of the binary systems are all larger than that of II-12-EO2. The interaction parameters β of the two binary systems were calculated, and the negative values of β indicate the existence of synergism in surface tension reduction efficiency, mixed micelle formation and surface tension reduction effectiveness.