Binary Surfactant Research Articles

Characterization of Phosphate‐Free Detergent Powders Incorporated with Palm C16 Methyl Ester Sulfonate (C16MES) and Linear Alkyl Benzene Sulfonic Acid (LABSA)

AbstractLaboratory and pilot scale investigations were carried out on phosphate‐free detergent (PFD) formulations comprising binary anionic surfactants of C16 palm methyl ester sulfonates (C16MES) and linear alkyl benzene sulfonic acid (LABSA) with the aim of maximizing the incorporation of C16MES into low density detergent powders without compromising the detergency and other significant properties. Initial laboratory experiments revealed that the detergent powder resulting from C16MES/LABSA with a 50:50 ratio and pH 7–8 has acceptable detergency stability over 1 week of accelerated ageing test at 50 °C and 85 % relative humidity. Subsequent experiments were carried out in a 5‐kg/h‐capacity pilot spray dryer using PFD formulations of C16MES/LABSA over the whole range of weight ratios under the same pH of 7–8. The concentration of the detergent slurry and cleaning performance (detergency, foaming ability and wetting power) of the resulting spray dried detergent powder (SDDP) were evaluated. C16MES/LABSA in a 40:60 ratio was selected as the ideal formulation based on its optimum detergent slurry concentration and comparable cleaning performance against the control formulation. Further environmental tests have confirmed that SDDP obtained from the ideal formulation is readily biodegradable (60 % in 13 days) and exhibits low eco‐toxicity properties (LC50 of 11.3 mg/L).

Synergistic adsorption of MIBC/CTAB mixture at the air/water interface and applicability of Gibbs adsorption equation.

The synergistic adsorption of a binary surfactant mixture was investigated by tensiometry and neutron reflectometry. The results directly contradicted the conventional Gibbs adsorption equation. The accompanied molecular simulation demonstrated a multilayer arrangement at the synergic conditions, with three distinctively oriented water layers. The positive synergism can be explained by considering the relationship between water orientation and surface tension, in a similar manner to Langmuir's proposal in 1920s. In spite of the supporting evidence, the relationship has not been quantified in literature. The molecular orientation and arrangement are not included in the current theoretical framework, which simplifies the adsorbed zone into a single monolayer. A new theoretical framework is needed to properly quantify the interfacial adsorption for the mixed surfactant systems.

Synthesis and Catalytic Activity of Fe-MCM-41 Nanoparticles

Mesostructured Fe-MCM-41 nanoparticles have been hydrothermally prepared for the first time with assistance of binary surfactants (CTAB and F127). The formation of nanoparticles consists of two steps, that is, the hydrolysis of silica precursor via catalysis by an acidic ferric salt, followed by facile assembly into mesostructured nanocomposites with cationic micelles by addition of condensation catalyst. In the hydroxylation of phenol with aqueous H2O2, Fe-MCM-41-NP displayed higher activity than a Fe-MCM-41 sample with normal particle size (Fe-MCM-41-LP).

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.

Microencapsulation of a fatty acid with Poly(melamine–urea–formaldehyde)

The main purpose of this study is to obtain leakage-free, thermally stable decanoic acid microcapsules (microPCMs) for thermal energy storage applications. Decanoic acid (capric acid) is an environmentally friendly fatty acid since it is obtained from vegetable and animal oils. MicroPCMs were prepared with different capsule wall materials via a one-step in situ polymerization technique. The properties of microencapsulated PCMs have been analyzed by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analyzer (TGA), Fourier transform infrared (FTIR) spectra analysis and particle size analyzer. The microPCMs prepared using Poly(urea–formaldehyde) (PUF) exhibit higher heat capacities and the microPCMs prepared using Poly(melamine–formaldehyde) (PMF) exhibit higher thermal stabilities. In order to obtain microPCMs with better properties such as suitable latent heat and better heat resistance at high temperatures, we microencapsulated decanoic acid with Poly (melamine–urea–formaldehyde) (PMUF). Furthermore, the effects of surfactants on microPCMs with PMUF were investigated by SEM, a particle size analyzer, DSC, and TGA. The results show that the binary surfactant system was a suitable emulsifier for this process. We determined that the melting temperature was close to 33°C, the latent heat storage capacity was about 88J/g, and the mean particle diameter was 0.28μm for microPCMs with PMUF. We recommend decanoic acid microencapsulated with PMUF for thermally stable and leakage-free applications above 95°C.

Competitive solubilization of low-molecular-weight polycyclic aromatic hydrocarbons mixtures in single and binary surfactant micelles

Abstract The present study aims to assess mutual interaction among low-molecular-weight polycyclic aromatic hydrocarbons (LMW PAHs), predominant contaminants at petroleum contaminated sites, in nonionic, anionic and their mixed micelles. Cosolubilization effects were evaluated by the molar solubilization ratio, the micelle-water partition coefficient and the deviation ratio. Two conditions existed: (i) naphthalene/phenanthrene and naphthalene/fluorene, with significant different hydrophobicities, showed synergistic effect, a new finding compared to previous observations that no more than one solute’s solubility would increase when two solubilizates coexisted, e.g. solubility of naphthalene and phenanthrene in Triton X-100 was increased by 20.8% and 38.5% when cosolubilized, respectively and (ii) phenanthrene/fluorene, with similar hydrophobicity, exhibited inhibitive effect due to competition for the same solubilization sites, i.e. solubility of phenanthrene and fluorene in Triton X-100 was decreased by 36.1% and 6.5% when cosolubilized, respectively. Solubility of PAHs with higher log K ow gained larger enhancement. Synergism was stronger in bisolutes solubilization system where more PAHs could solubilize in the micellar shell region. Solubility inhibition was more intense to PAHs with lower log K ow . The cosolubilization trends were consistent in single and mixed surfactant systems, whereas the enhancing and suppressive extent, on the whole, were weakened and strengthened with increasing mole ratio of anionic surfactant in the mixed micelles because of reduction in micelle size. This study suggested the significance of considering multi-solutes’ interaction to estimate solubilization power of surfactants for selective separation of LMW PAHs from water and soil.

Overgrowth of Gold Nanorods by Using a Binary Surfactant Mixture

Seed-mediated surfactant-assisted growth is widely used as the most effective method for gold nanorod (NR) synthesis. Using prepared nanorods as seeds for further overgrowth can increase the dimensional tunability of the final particles. However, overgrowth in usual cetyltrimethylammonium bromide (CTAB) surfactant solutions leads to poor control of the final particle shape and size. In this work, we report an improved strategy to demonstrate the controllable overgrowth of gold NRs in the binary surfactant mixture sodium oleate (NaOL) + CTAB. This approach overcomes the difficulty of growing NR suspensions with small amounts of impurities. By controlling the total amount of added NR seeds, it is possible to tune the average length, diameter, and plasmon resonances of overgrown particles in a wide range. Together with the original NaOL + CTAB method developed by Murray and co-workers ( Nano Lett. 2013 , 13 , 555 ), this overgrowth approach expands the dimensional and plasmonic tunability of the fabrication technology without any decrease in the monodispersity and purity of samples.

Detergency stability and particle characterization of phosphate-free spray dried detergent powders incorporated with palm C16 methyl ester sulfonate (C16MES).

Phosphate-free spray dried detergent powders (SDDP) comprising binary anionic surfactants of palm C16 methyl ester sulfonate (C16MES) and linear alkyl benzene sulfonic acid (LABSA) were produced using a 5 kg/h-capacity co-current pilot spray dryer (CSD). Six phosphate-free detergent (PFD) formulations comprising C16MES/LABSA in various ratios under pH 7-8 were studied. Three PFD formulations having C16MES/LABSA in respective ratios of 0:100 (control), 20:80 and 40:60 ratios were selected for further evaluation based on their optimum detergent slurry concentrations. The resulting SDDP from these formulations were analysed for its detergency stability (over nine months of storage period) and particle characteristics. C16MES/LABSA of 40:60 ratio was selected as the ideal PFD formulation since its resulting SDDP has consistent detergency stability (variation of 2.3% in detergency/active over nine months storage period), excellent bulk density (0.37 kg/L), fine particle size at 50% cumulative volume percentage (D50 of 60.48 μm), high coefficient of particle size uniformity (D60/D10 of 3.86) and large spread of equivalent particle diameters. In terms of surface morphology, the SDDP of the ideal formulation were found to have regular hollow particles with smooth spherical surfaces. Although SDDP of the ideal formulation have excellent characteristics, but in terms of flowability, these powders were classified as slightly less free flowing (Hausner ratio of 1.27 and Carr's index of 21.3).

Synthesis and Properties of N,N′-Bis(Sodium Lauryl Acyl Proyl Acid) Ethylenediamine

Abstract The Gemini surfactant, N,N′-bis(sodium lauryl acyl proyl acid) ethylenediamine, was synthesized and symbolized as DLMC. The surface chemical properties and micellar behavior of DLMC with polyethylene oxide lauryl ether (C12E6) in 0.1 mol · L−1 sodium bromide aqueous solution were investigated by surface tention measurements at 298 K. The critical micelle concentration (cmc) of DLMC is 1.01 × 10−4 mol L−1, and the cmc values of the binary surfactant system are all lower than those of pure constituent surfactants. The interaction parameter β of the binary surfactant system was calculated, which indicates the existence of synergism in surface tension reduction efficiency, mixed micelle formation and surface tension reduction ability.

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.

Physico-chemical properties of bile salt-Tween 80 mixed micelles in the viewpoint of regular solution theory

In this work mixed micelles of Na salts of bile acids and Tween 80 are studied. In the experiment, number and orientation of OH and oxo groups in the steroid skeleton of bile acid anion varies. In every investigated mixture, mole fraction of Tween 80 (α) varies from 0.05 to 0.5 of the total surfactant concentration. Critical micelle concentrations of binary surfactant mixtures are determined by tensiometric and conductometric methods (modified Philips method of data processing). By employing regular solution theory for every studied binary surfactant mixture, values of interaction coefficient (β1,2) are determined. Based on the obtained β1,2 values, investigated bile acid anions form two groups. Group I consists of bile acids having only OH groups attached to the steroid skeleton. Characteristics of mixed micelles of this group are negative values of β1,2 for α to 0.1 (synergistic effect between different types of the micelle building units), and positive values of β1,2 for α over 0.1 (antagonistic effect). This change of sign of β1,2 as a function of α can be explained by phase transformation in mixed micelle as a pseudophase, and due to rigid geometry of cis-oleic residue of Tween 80. Group II is formed of bile acid anions having one or more oxo groups in the steroid skeleton. Mixed micelles of Tween 80 and group II of bile acid anions are characterized by positive β1,2 values in the whole investigated range of α. Based on the intensity measurements at different temperatures of first (I1) and third (I3) vibrational bands of pyrene (probe molecule) emission spectrum as a function of total surfactant concentration, it can be concluded that mixed micelles having Tween 80 are less rigid than mixed micelles having Tween 40. This also indicates that in hydrophobic domain of mixed micelles, cis-oleic residues are more difficult to pack together compared to the palmitic residues of Tween 40.

The thermodynamic properties of AOT/Dynol-604 mixed surfactant solutions

Volumetric properties of mixed surfactants of Bis(2-ethylhexyl) sodium sulfosuccinate (AOT) and Ethoxylated-2,5,8,11-tetramethyl-6-dodecyne-5,8-diol (Dynol-604) in aqueous solutions with various compositions have been studied at 298.15K by density measurements. The apparent molar volumes, the partial molar volumes, the critical micelle concentrations, and the apparent molar volumes in the monomeric and micellar states of the binary mixed surfactants with various compositions were determined. Moreover, the results were used to calculate the micellar compositions, the excess free energies of mixing, the activity coefficients and the interaction parameter between two surfactants for the mixed micelles based on the Rubingh’s formulism.

Computer Simulation–Molecular-Thermodynamic Framework to Predict the Micellization Behavior of Mixtures of Surfactants: Application to Binary Surfactant Mixtures

We present a computer simulation-molecular-thermodynamic (CSMT) framework to model the micellization behavior of mixtures of surfactants in which hydration information from all-atomistic simulations of surfactant mixed micelles and monomers in aqueous solution is incorporated into a well-established molecular-thermodynamic framework for mixed surfactant micellization. In addition, we address the challenges associated with the practical implementation of the CSMT framework by formulating a simpler mixture CSMT model based on a composition-weighted average approach involving single-component micelle simulations of the mixture constituents. We show that the simpler mixture CSMT model works well for all of the binary surfactant mixtures considered, except for those containing alkyl ethoxylate surfactants, and rationalize this finding molecularly. The mixture CSMT model is then utilized to predict mixture CMCs, and we find that the predicted CMCs compare very well with the experimental CMCs for various binary mixtures of linear surfactants. This paper lays the foundation for the mixture CSMT framework, which can be used to predict the micellization properties of mixtures of surfactants that possess a complex chemical architecture, and are therefore not amenable to traditional molecular-thermodynamic modeling.

Properties of Binary Surfactant System of Alkyl Polyglycosides and α-Sulphonated Fatty Acid Methyl Ester

Abstract Surface tension, fluorescence, zeta potential, dynamic light scattering and viscosity measurements have been used to investigate the properties of binary surfactant system of alkyl polyglycosides (APG) and α-sulphonated fatty acid methyl ester (MES). Through surface tension measurements, critical micelle concentration (CMC) of the mixture for different mixing mole fractions is determined and the values are all lower than those of pure constituent surfactants. Ideal CMC, molecule interaction parameters β and B have been calculated, and all these parameters indicate nonideal behavior and attractive interactions between the surfactant molecules. The micelle aggregation numbers (Nagg ) and the zeta potential (ζ) values of the binary surfactant system fall between those of constituent surfactants. The hydrodynamic radius (Rh ) of mixed micelle first increases and then decreases with the addition of MES. All these results show that nonionic surfactants facilitate the formation of larger micelles. The viscosities (η) of the mixtures are all lower than those of the pure component surfactants and with the addition of sodium chloride, the viscosity of mixture first increases rapidly and then decreases.

Wettability of polymers by aqueous solution of binary surfactants mixture with regard to adhesion in polymer–solution system II. Critical surface tension of polymers wetting and work of adhesion

The values of the surface tension of the aqueous solution of CTAB+TX-100, CTAB+TX-114 and TX-100+TX-114 mixtures and those of the contact angle for the same solutions on PTFE, PMMA and nylon 6 surface were applied for the studies of the correlation between the critical surface tension of PTFE, PMMA and nylon 6 wetting and their surface tension as well as the influence of the kind, concentration and composition of the aqueous solutions of binary mixtures of surfactants and the adhesion to those polymers. From these studies it results that the critical surface tension of PTFE wetting by the investigated solutions is somewhat higher than its surface tension determined from the contact angles for n-alkanes. However, the critical surface tension of PMMA and nylon 6 wetting is lower than their surface tension determined by using the van Oss et al. approach to the interfacial tension. The critical surface tension of PMMA and nylon 6 wetting was also compared to their surface tension calculated from the Neumann equation. It was found that there is agreement between these values if the surface tension of these polymers was determined on the basis of the solution surface tension and contact angle data corresponding to the concentration equal or higher than the critical micelle concentration.

Wettability of polymers by aqueous solution of binary surfactants mixture with regard to adhesion in polymer–solution system I—Correlation between the adsorption of surfactants mixture and contact angle

Wettability of polytetrafluoroethylene (PTFE), polymethyl methacrylate (PMMA) and nylon 6 by aqueous solutions of binary mixtures composed of cetyltrimethylammonium bromide (CTAB) with p-(1,1,3,3-tetramethylbutyl)-phenoxypolyoxyethylene glycols, Triton X-100 (TX-100) and Triton X-114 (TX-114) with regard to the tendency of their adsorption at the water–air and polymer–water interfaces was considered on the basis of the measured values of the contact angle, the dependence between the adhesion and surface tension as well as the Gibbs surface excess concentration. It was shown that the wettability of PTFE, PMMA and nylon 6 depends on the concentration and composition of the binary mixtures of surfactants in water and the best wettability occurs at the concentration of the mixtures corresponding to the critical micelle concentration of their solutions. However, at the lower concentrations the synergetic effect in the wettability of polymers by the CTAB+TX-100 and CTAB+TX-114 mixtures takes place. This effect was confirmed by the standard Gibbs free energy of adsorption of binary mixtures of surfactants at the polymer–water interface calculated on the basis of the Gu and Zhu equation. The standard Gibbs free energy of adsorption being a measure of the efficiency of a given mixture to adsorb at the polymer–water interface changes in a different way from the maximal Gibbs surface excess concentration of these mixtures calculated from the Gibbs isotherm equation which suggests that the changes of the efficiency of the adsorption process are not proportional to its effectiveness.

Janus Cages of Bilayered Polymer–Inorganic Composites

Janus cages with a bilayer polymer–inorganic composite shell are synthesized by an emulsion interfacial self-organized sol–gel process followed by a polymer grafting onto the interior surface containing a vinyl group. Binary surfactants experience a phase separation to create transverse channels across the shell. The Janus cages can be functionalized by either growing responsive polymers or integrating with functional nanoparticles. They are promising in controlled loading and triggered release of desired materials under guidance.