Ternary Surfactant Mixtures Research Articles

Enhanced solubility of methyl ester sulfonates below their Krafft points in mixed micellar solutions

HypothesisMethyl ester sulfonates (MES) show limited water solubility at lower temperatures (Krafft point). One way to increase their solubility below their Krafft points is to incorporate them in anionic surfactant micelles. The electrostatic interactions between the ionic surfactant molecules and charged micelles play an important role for the degree of MES solubility. ExperimentsThe solubility and electrolytic conductivity for binary and ternary surfactant mixtures of MES with anionic sodium alpha olefin sulfonate (AOS) and sodium lauryl ether sulfate with two ethylene oxide groups (SLES-2EO) at 5 °C during long-term storage were measured. Phase diagrams were established; a general phase separation theoretical model for their explanation was developed and checked experimentally. FindingsThe binary and ternary phase diagrams for studied surfactant mixtures include phase domains: mixed micelles; micelles + crystallites; crystallites, and molecular solution. The proposed general phase separation model for ionic surfactant mixtures is convenient for construction of such complex phase diagrams and provides information on the concentrations of all components of the complex solution and on the micellar electrostatic potential. The obtained maximal MES mole fraction of transparent micellar solutions could be of interest to increase the range of applicability of MES–surfactants.

Ternary Mixed Micelle Hexadecyltrimethylammonium Bromide-Dodecyltrimethylammonium Bromide-Sodium Deoxycholate: Gibbs Free Energy of Mixing and Excess Gibbs Energy of Mixing.

Pharmaceutical, food, and cosmetic formulations often contain binary or ternary surfactant mixtures with synergistic interactions amongst micellar building blocks. Here, a ternary mixture of the surfactants hexadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, and sodium deoxycholate is examined to see if the molar fractions of the surfactants in the ternary mixed micellar pseudophase are determined by the interaction coefficients between various pairs of the surfactants or by their propensity to self-associate. Critical micelle concentrations (CMC) of the analyzed ternary mixtures are determined experimentally (spectrofluorimetrically using pyrene as the probe molecule). Thermodynamic parameters of ternary mixtures are calculated from CMC values using the Regular Solution protocol. The tendency for monocomponent surfactants to self-associate (lower value of CMC) determines the molar fractions of surfactant in the mixed micelle if there is no issue with the packing of the micelle building units of the ternary mixed micelle. If a more hydrophobic surfactant is incorporated into the mixed micelle, the system (an aqueous solution of surfactants) is then the most thermodynamically stabilized.

Experimental Investigation on Spontaneous Imbibition of Surfactant Mixtures in Low Permeability Reservoirs.

Spontaneous imbibition of surfactants could efficiently enhance oil recovery in low permeability sandstone reservoirs. The majority of studies have considered the application of individual surfactants to alter wettability and reduce interfacial tension (IFT). However, a significant synergistic effect has been reported between different types of surfactants and between salts and surfactants. Therefore, this study systematically studied the capability of a binary surfactant mixture (anionic/nonionic) and a ternary surfactant mixture (anionic/nonionic/strong base-weak acid salt) in imbibition enhanced oil recovery (IEOR). The interfacial properties and the cores' wettability were explored by IFT and contact angle measurements, respectively. Subsequently, the imbibition performances of different types of surfactant solutions were discussed. The results suggested that the surfactants' potential to enhance oil recovery followed the order of ternary surfactant mixture > binary surfactant mixture > anionic > nonionic > amphoteric > polymer. The ternary surfactant mixture exhibited strong capacity to reverse the rock surface from oil-wet (125°) to strongly water-wet (3°), which was more significant than both binary surfactant mixtures and individual surfactants. In addition, the ternary surfactant mixture led to an ultralow IFT value of 0.0015 mN/m, achieving the highest imbibition efficiency (45% OOIP). This research puts forward some new ideas on the application of the synergistic effects of surfactants in IEOR from low-permeability sandstone reservoirs.

On the relationship between the properties of planar structures of non-ionic surfactants and their vesicular analogues – Niosomes

In recent years, the study of niosomes as nanocarriers alternative to liposomes has received increasing attention. In contrast to well-studied liposome membranes, many aspects of the behavior of analogous niosome bilayers have not been studied. This paper considers one of these aspects related to the communication between the physicochemical properties of planar and vesicular objects. We present the first results of comparative studies of Langmuir monolayers of binary and ternary (with cholesterol) mixtures of non-ionic surfactants based on sorbitan esters and niosomal structures assembled from the same materials. The Thin-Film Hydration (TFH) method in the gentle shaking version was used to produce the particles of large sizes, while small unilamellar high quality vesicles with a unimodal distribution of particles were prepared by TFH using ultrasonic treatment and extrusion. An analysis of the structural organization and phase state of monolayers based on compression isotherms and supplemented by thermodynamic calculations, as well as the results of determining the particle morphology, polarity and microviscosity of niosome shells, made it possible to obtain fundamental data on the intermolecular interactions of the components and their packing in shells and to relate these data to the properties of niosomes. This relationship can be used to optimize the composition of niosome membranes and predict the behavior of these vesicular systems. It was shown that cholesterol excess creates regions of bilayers with increased rigidity (like “lipid rafts”), which hinders the process of folding film fragments into small niosomes.

Interaction and micellar behavior of ternary mixture of amphoteric amino sulfonate surfactant with traditional anionic and nonionic surfactants: Effect of hydrophilicity

The micellization and the molecular interaction behaviors for two ternary mixtures constituted by an amphoteric sodium 3-(n-dodecyl ethylenediamino)-2-hydroxypropyl sulfonate (C12AS), an anionic sodium dodecylbenzene sulfonate (SDBS) and a nonionic octylphenol polyoxyethylated ether with the number (n) of oxyethylene glycol ethers OP-n (n = 10 or 7) in aqueous solution were investigated using the tensiometry and the effect of hydrophilicity on them was also discussed. In the framework of pseudophase separation model and based on the regular solution theory, the related micellization parameters including the mixed critical micelle concentration (cmc) values in the ideal and real cases, the activity coefficients and the compositions in mixed micelle, etc. and thermodynamic parameters were estimated by the Clint’s model and the Rubingh’ model. The mixed cmc value is dependent on the composition in aqueous solution and influenced by the hydrophilicity of nonionic surfactant. With increasing the nonionic in ternary mixture, the mixed cmc value is initially decreased and then slightly rise. An increasing in the hydrophilicity of nonionic will make the minimum value of mixed cmc be increased from 1.299 mM to 1.705 mM. The resulting phenomena can be explained reasonably by the electrostatic effect, the steric hindrance, the hydrogen bonding, etc. Thermodynamic data indicate that the contribution of entropy or enthalpy plays a vital role on the spontaneous process of micellization and the share of entropy or enthalpy in free energy change is dependent largely on the amount of nonionic surfactant and the hydrophilicity. In ternary mixtures of C12AS/SDBS/OP-10, an increase in an amount of OP-10 will induce the change from the enthalpy-driven micellization process to the entropically favorable process. Once an abundant amount of OP-7 is added, while, the enthalpy will make a main contribution on the micellization process, which can be described by the drop in the share of entropy at the composition (0.6970/0.0000/0.3030) of ternary mixture from 0.6478 to 0.4901. These findings will help with understanding the molecular interaction behavior for the ternary surfactant mixture and the effect of the addition of nonionic surfactant and its hydrophilicity.

Analyzing the surfactant classification confusion through the HLD formulation equation

The qualitative presentation from Winsor on an interfacial balance of interactions between the surfactant and the oil and water phases has been transformed into a multivariable linear equation so-called hydrophilic-lipophilic deviation (HLD). This relation involves at least 6 independent variables (surfactant head and tail specifications, water salinity, oil nature, temperature, and pressure) with a MacLaurin series first order approximation, i.e., a linear multivariable expression. After 40 years of practical experience, it can be said that the HLD relation matches well the experimental data, with only very few exceptions with complex mixtures. Herein, we clear the confusion concerning the meaning and the mathematical handling of the surfactant parameter in the HLD equation. We start with a presentation of simple surfactant systems with only 4 parameters (water salinity, oil nature, surfactant nature, and temperature) as was done 40 years ago. Later, we present a critical discussion on the surfactant term, concerning binary surfactant systems, and on strategies for applications in ternary surfactant mixtures. We have found that the surfactant parameters can only be compared in a series of surfactants with the same head group, where the surfactant parameter is a linear function of the surfactant tail length.

Foaming systems for foam flooding with both high foaming performance and ultralow oil/water interfacial tension

In foam flooding ultralow oil/water IFT and superior foaming performance are usually not compatible, because both are achieved by surfactants at different conditions. In this paper we constitute a mixed surfactant system which can achieve both ultralow oil/water IFT and high foaming performance concurrently by means of synergistic effects between different surfactants.Aiming at the reservoir conditions of Daqing oilfield, China (45 °C, total salinity 6,778 mg/L, pH = 8–9), a ternary surfactant mixture SDS/DTAB/APG at a mole fraction ratio of 0.36/0.24/0.4 was found to be an optimal surfactant system by which ultralow IFT and high foaming performance could be achieved concurrently at wide total concentrations (2–6.5 mM). Specifically, at a total concentration of 5 mM the IFT can be reduced to as low as 2.9 × 10-5 mN/m whereas the composite foaming index in the presence of crude oil can reach as high as 936 Ls. The SDS/DTAB binary mixture dominates the mixed monolayer at both air/water and oil/water interfaces as indicated by a high pseudo mole fraction of 0.94. The strong attraction between anionic/cationic surfactants endows densely packed monolayers which are responsible for the achievement of low surface tension and ultralow IFT, whereas the nonionic surfactant APG behaves as a solubilizer of the SDS/DTAB binary mixture in bulk as well as a stabilizer of the bubbles and emulsified oil droplets, which synergistically endows a high foaming performance to the ternary surfactant system. Based on the relevant principle more mixed surfactant systems may be found which are significant for improving efficiency of foam flooding.

Prediction of Aqueous Solution Surface Tension of Some Surfactant Mixtures and Composition of Their Monolayers at the Solution—Air Interface

Measurements of the surface tension of the aqueous solution of SDDS mixture with fluorocarbon surfactants (FC) were carried out and considered in light of the surface tension of aqueous solutions of individual surfactants. Similar analyses were made for many other aqueous solutions of binary and ternary mixtures, taking into account the literature data of the surface tension of aqueous solutions of TX100, TX114, TX165, SDDS, SDS, CTAB, CPyB and FC. The possibility of predicting the surface tension of the aqueous solution of many surfactant mixtures from that of the mixture components using both the Szyszkowski, Fainerman and Miller and Joos concepts was analyzed. The surface tension of the aqueous solutions of surfactant mixtures was also considered based on the particular mixture component contribution to the water surface tension reduction. As a result, the composition of the mixed surface layer at the solution–air interface was discussed and compared to that which was determined using the Hua and Rosen concept. As follows from considerations, the surface tension of the aqueous solution of binary and ternary surfactant mixtures can be described and/or predicted.

Molecular interaction and foaming property of the mixtures of hydrocarbon, fluorocarbon and silicone surfactants

Fluorocarbon surfactants are inevitably involved in industrial applications in combination with hydrocarbon and silicone surfactants, but properties of the ternary mixed system of hydrocarbon, fluorocarbon and silicone surfactants have received little attention, especially foaming ability. In this study, surface activity and aggregation behavior of the ternary mixed system of anionic hydrocarbon (SDS), cationic fluorocarbon (FC-134) and nonionic silicone surfactants (OFX-5211) are studied systematically in order to investigate molecular interaction. Foaming ability of the ternary mixed system is evaluated by Ross-Miles method. Surface activity is characterized by surface tension. Aggregation behavior is obtained by using cryo-transmission electron microscopy (Cryo-TEM). The results show that intense interaction among molecules exists in the ternary surfactant mixture. FC-134 molecules show the interaction with other two surfactant molecules at air/liquid interface and strongest ability to absorb into air/liquid interface. Large vesicles of binary mixture of SDS/OFX-5211 are transformed into irregular micelles upon addition of FC-134. And wormlike micelles of binary mixture of SDS/FC-134 disappeared upon addition of OFX-5211. The foaming ability of the ternary mixtures is higher than that of any of individual surfactant or binary mixtures of surfactants. The intense interaction among molecules promotes the synergistic effect of foaming ability of the ternary mixtures. This study can provide a guidance for the scientific application of hydrocarbon, fluorocarbon and silicone surfactants.

Microrheological study of ternary surfactant-biosurfactant mixtures.

The main objective of this paper is to understand the rheological impact of rhamnolipids biosurfactant (mono/dirhamnolipids mixture, CCB) on a common personal care mixed surfactants system: anionic sodium laureth sulfate (SLES) and zwitterioniccocamidopropyl betaine (CAPB). The ternary biosurfactant/surfactants mixtures were evaluated at three different formulation conditions. The experimental results can provide a formulation guideline when applying rhamnolipids in cosmetics and personal careproducts. Traditional mechanical rheometer was used to measure bulk viscosity and lower frequency rheological behaviour of ternary surfactant mixtures. Diffusing wave spectroscopy(DWS) was utilized to access rheological responses at high frequency regime.Structural parameters such as contour length, entanglement length and persistence length of wormlike micelles in the anionic/zwitterionic/biosurfactant mixturescan be extractedfrom the rheological data gathered by DWS. Maxwellian type responsewas present in SLES/CAPB/CCB system whichindicated theformation of wormlike micelle. Contour length of wormlike micelle formed by SLES/CAPB reduced from 445.8 to 88.37nm with only 2 wt% addition of CCB. In the samesystem,viscosity decreased and shorter relaxation time were observed. Addition of sodium chloridebuilt the viscosity of SLES/CAPB/CCB to an extent by screening charges between surfactant head groups. Highest viscosity of SLES/CAPB/CCB (10 wt%, 2wt% and 4wt% respectfully)was observed when sodium chloride concentration was at 4 wt%. In the same SLES/CAPB/CCB system, pH impacted the system's rheological response significantly. Due to the zwitterionic nature of CAPB, it becamemore cationic at lower pH while rhamnolipids becamemore nonionic. SLES stillmaintained its anionic nature at low pH and this promoted the interaction between CAPB and SLES. At lower pH, overall loss and storage modulus exhibitedhigher values while longer relaxation times were observed. Increase in micelles contour length under lower pH conditions were shown by the DWS data. This preliminary rheological and microstructure study of the complex biosurfactant/surfactants ternary systems revealed the effect of formulation conditions on the mixtures rheological responses.

Micellization and interactions for ternary mixtures of amino sulfonate surfactant and nonionic octylphenol polyoxyethylene ethers in aqueous solution: 1 Blending with nonionic surfactants with smaller numbers of hydrophilic unit

The micellization and the molecular interactions for the ternary mixture of an amphoteric surfactant, sodium 3-(N-dodeyl ethylenediamino)-2-hydropropyl sulfonate (C12AS), with two nonionic surfactants, octylphenol polyoxyethylene ethers with different number (n) of oxyethylene glycol ethers (OP-n), e.g., OP-10 and OP-7, or OP-10 and OP-4, in aqueous solution were investigated by the tensiometry. Specifically, the effect of the addition of OP-7 or OP-4 on the micellization of binary mixture of C12AS/OP-10 was probed. The addition can decrease the value of mixed critical micellar concentration (cmc) and change the composition of mixed micelle. Thermodynamic data indicate that though the addition decreases the contribution of entropy to the process of micellization, its overwhelming effect is not changed, or in other words, the effect of the addition is relatively limited in this investigation. These findings may help with understanding the molecular interaction for the ternary surfactant mixture constituted by commercial surfactants, which are usually not single but the mixture of homologues.

Micellization and interaction for ternary mixtures of amino sulfonate surfactant and nonionic octylphenol polyoxyethylene ethers in aqueous solution: 2 blending with nonionic surfactant with a longer or shorter hydrophilic chain

The micellization behavior of the ternary mixture of an amphoteric sodium 3-(N-dodecyl ethylenediamino)-2-hydropropyl sulfonate (C12AS) with two nonionic surfactants, octylphenol polyoxyethylene ether (OP-n, where n is the number of hydrophilic unit oxyethylene glycol ethers, n = 4, 7, 10), was investigated using both the tensiometry and the 1H NMR technique. Also, the effect of the addition of nonionic surfactant with a longer or shorter hydrophilic chain, e.g., OP-10 or OP-4, on the micellization of the binary mixture of C12AS/OP-7 with a maximum synergism was probed. Based on the regular solution theory, thermodynamic models were adopted to obtain the composition, activity coefficient of mixed micelle and some thermodynamic parameters. The addition of OP-10 or OP-4 into the binary mixture of C12AS/OP-7 induces the change in the mixed critical micelle concentration, which can be explained by the change in the composition of mixed micelle and the effect of hydrophilic chain. Thermodynamic data show that the addition of OP-10 or OP-4 results in the change from the enthalpy overwhelming process of micellization to the entropy-driven process. The chemical shift of proton in the terminal hydroxy group of OP-n in binary or ternary surfactant mixture is also adopted to describe the obtained results. The findings will help with understanding the interaction behavior between molecules in the multicomponent mixture, especially, the effect of the addition of homologues or other components on the properties of surfactant formulation.

The performance of surfactant mixtures at low temperatures

Optimising detergency at lower temperatures is of increasing interest due to environmental and economic factors, and requires a greater understanding of the effects of temperature on the adsorption of surfactant mixtures at interfaces.The adsorption properties of surfactant mixtures and biosurfactant/surfactant mixtures have been studied at room temperatures and at temperatures below ambient using surface tension and neutron reflectivity measurements.For the ternary surfactant mixture of octaethylene monododecyl ether, C12E8, sodium dodecyl 6-benzene sulfonate, LAS, and sodium dioxyethylene glycol monododecyl sulfate, SLES, the surface tension at the air-water interface increases with decreasing temperature. In contrast, there is a notable reduction in the increase in the surface tension with a decrease in temperature from 25 °C to 10 °C for the 5 component rhamnolipid/surfactant mixture of the mono-rhamnose, R1, and di-rhamnose, R2, with C12E8/LAS/SLES. The associated neutron reflectivity data for the ternary C12E8/LAS/SLES mixture and the significant observation is that the 3, 4, and 5-component mixtures containing rhamnolipids in conjunction with the other surfactants show changes in composition and adsorbed amounts of the individual components which are close to the experimental error. However the significant observation is that the neutron reflectivity data indicate that the improved surface tension tolerance at lower temperatures is associated with the dominance of the rhamnolipid adsorption in such mixtures.Hence the introduction of the rhamnolipids provides a tolerance to the adverse effects associated with reduced temperatures, and a potential for improved detergency at relatively low temperatures.

Impact of Electrolyte on Adsorption at the Air-Water Interface for Ternary Surfactant Mixtures above the Critical Micelle Concentration.

The composition of the air-water adsorbed layer of the ternary surfactant mixture, octaethylene monododecyl ether, C12E8, sodium dodecyl 6-benzenesulfonate, LAS, and sodium dioxyethylene glycol monododecyl sulfate, SLES, and of each of the binary mixtures, with varying amounts of electrolyte, has been studied by neutron reflectivity. The measurements were made above the mixed critical micelle concentration. In the absence of electrolyte adsorption is dominated by the nonionic component C12E8 but addition of electrolyte gradually changes this so that SLES and LAS dominate at higher electrolyte concentrations. The composition of the adsorbed layer in both binary and ternary mixtures can be quantitatively described using the pseudo-phase approximation with quadratic and cubic interactions in the excess free energy of mixing (GE) at both the surface and in the micelles. A single set of parameters fits all the experimental data. A similar analysis is effective for a mixture in which SDS replaces SLES. Addition of electrolyte weakens the synergistic SLES-C12E8 and LAS-C12E8 interactions, consistent with them being dominated by electrostatic interactions. The SLES-LAS (and SDS-LAS) interaction is moderately strong at the surface and is little affected by addition of electrolyte, suggesting that it is controlled by structural or packing factors. Most of the significant interactions in the mixtures are unsymmetrical with respect to composition, with the minimum in GE at the 1:2 or 2:1 composition. There is a small structural contribution to the LAS-C12E8 interaction that leads to a minimum intermediate in composition between 1:2 and 1:1 (LAS:C12E8) and to a significant residual GE in strong electrolyte.

Surface Adsorption in Ternary Surfactant Mixtures above the Critical Micelle Concentration: Effects of Asymmetry on the Composition Dependence of the Excess Free Energy.

The composition of the adsorbed layer of a ternary surfactant mixture at the air-water interface has been studied by neutron reflectivity. The adsorption of the ternary mixture of octaethylene monododecyl ether (C12E8) sodium dodecyl 6-benzene sulfonate (LAS), and sodium dioxyethylene glycol monododecyl sulfate (SLES), as well as each of the binary mixtures, at solution concentrations greater than the mixed critical micelle concentration is highly nonideal. In the ternary mixture, the surface adsorption is dominated by C12E8 and LAS, and there is little SLES at the interface. The departure from ideality in the binary mixtures can be quantitatively described by applying the pseudophase approximation with quadratic and cubic terms in the excess free energy of mixing (GE) both at the surface and in the micelles. The same parameters that describe the binary interactions give a quantitative fit to the adsorbed fractions in the ternary mixture over a wide range of composition. A similar analysis is effective for the mixture containing sodium dodecyl sulfate instead of SLES. Of the set of six GE required to fit the ternary data, one is ideal (SLES-LAS) and three, LAS-C12E8 (micelle) and C12E8-SLES (micelle and surface), have minima occurring at a composition (mole fraction) of the anionic species of 1/3.

Self-assembly in dilute mixtures of non-ionic and anionic surfactants and rhamnolipd biosurfactants

The self-assembly of dilute aqueous solutions of a ternary surfactant mixture and rhamnolipid biosurfactant/surfactant mixtures has been studied by small angle neutron scattering. In the ternary surfactant mixture of octaethylene glycol monododecyl ether, C12E8, sodium dodecyl 6-benzene sulfonate, LAS, and sodium dioxyethylene monododecyl sulfate, SLES, small globular interacting micelles are observed over the entire composition and concentration range studied. The modelling of the scattering data strongly supports the assumption that the micelle compositions are close to the solution compositions. In the 5-component rhamnolipid/surfactant mixture of the mono-rhamnose, R1, di-rhamnose, R2, rhamnolipids with C12E8/LAS/SLES, globular micelles are observed over much of the concentration and composition range studied. However, for solutions relatively rich in rhamnolipid and LAS, lamellar/micellar coexistence is observed. The transition from globular to more planar structures arises from a synergistic packing in the 5 component mixture. It is not observed in the individual components nor in the ternary C12E8/LAS/SLES mixture at these relatively low concentrations. The results provide an insight into how synergistic packing effects can occur in the solution self-assembly of complex multi-component surfactant mixtures, and give rise to an unexpected evolution in the phase behaviour.

Micelle co-assembly in surfactant/ionic liquid mixtures

HypothesisThe phase behavior of amphiphiles is known to depend on their solvent environment. The organic character of ionic liquids suggested the possibility to tune surfactant aggregation, even in the absence of water, by selection of appropriate ionic liquid chemistry. To that end the behavior of the surfactant sodium dodecylsulfate in a chemically similar imidazolium ionic liquid, 1-ethyl-3-methyl imidazolium ethylsulfate, was explored. ExperimentsThe solubility of sodium dodecylsulfate in 1-ethyl-3-methyl imidazolium ethylsulfate was determined, establishing the Krafft temperature. Tensiometry was performed to obtain interfacial properties such as the surface excess and area per molecule. Pulsed-field gradient spin-echo NMR was used to determine the diffusion coefficients of all the major species, including micelles, as a function of surfactant concentration. Importantly, all three methods provided consistent values for the critical micelle concentration. FindingsAnalysis of tensiometry data suggests, and is confirmed by NMR results, that the ionic liquid ions are incorporated along with surfactants into micelles, revealing a complex micellization behavior. In light of these findings past studies with ternary mixtures of surfactants, ionic liquids, and water may merit additional scrutiny. Given the large number of ionic liquids, this work suggests opportunities to further control micelle formation and properties.

Preparation of highly concentrated inverse emulsions of acrylamide‐based anionic copolymers as efficient water rheological modifiers

ABSTRACTHighly concentrated inverse anionic polymeric emulsions (with a solid content of up to 63 wt %) were prepared using a two‐step methodology: (i) First, acrylamide, acrylic acid, and its ammonium salts crosslinked copolymers were obtained by inverse emulsion polymerization, (ii) The water/volatile oil mixture was then separated from the heterogeneous system by vacuum distillation. To maintain sufficient stability during the reaction and distillation processes, a ternary surfactant mixture was used. A surface response methodology was employed to obtain the optimal values of the factors involved in both process and product specifications, and to maximize the high performance of these inverse anionic polymer emulsions. This yielded a product containing up to 63.2 wt % solids capable of achieving Brookfield viscosities as high as 40.3 Pa·s, using an aliquote of these concentrated inverse polymer emulsions (1.8 wt % in deionized water). Rheological characterization (oscillatory and rotational measurements) was carried out to evaluate the behavior of the diluted inverse anionic polymer emulsion in water thickening. The methodology developed can be used to formulate a wide range of viscoelastic (G″/G′) water‐based products from anionic water soluble polymers. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43502.

Electrochemical measurement, modeling, and prediction of corrosion inhibition efficiency of ternary mixtures of homologous surfactants in salt solution

The corrosion inhibition efficiency of different mixtures of three homologous surfactants, benzalkonium chlorides (BAC), was investigated using electrochemical measurements and modeling. The surface aggregation concentration (sac) and critical micelle concentration (cmc) of surfactant are useful to evaluate inhibition efficiency. A new cmc prediction model for ternary mixed homologous surfactants of interest has been developed. The model is applicable over a wide concentration range of dissolved salt in solution. The combination of the modified Langmuir adsorption model and the cmc prediction model provides a potential method for inhibition efficiency prediction of various mixed homologous surfactant systems at various dissolved salt concentrations.

Electrochemical Measurement and Modeling of Corrosion Inhibition of Ternary Mixtures of Homologous Surfactants

In the present study, the corrosion inhibition efficiency (IE) of different mixtures of three homologous cationic surfactants, benzalkonium chlorides (ADBAC), were investigated using electrochemical measurements. There is excellent agreement between IE measured from EIS and LPR of the discussed mixture of ADBAC surfactants: C12Cl/C14Cl/C16Cl=0.70/0.25/0.05. The calculated adsorption free energy indicates that the adsorption mechanism of mixtures 0.70/0.25/0.05 is a mixed form of physisorption and chemisorption. A new critical micelle concentration (CMC) prediction model for ternary mixtures of homologous surfactants, on the basis of previous work, is developed over a wide concentration range of salt from 0.2% to 5.0% NaCl. The developed corrosion IE prediction model based on CMC prediction is an effective method that can be used for corrosion IE prediction of various mixed surfactant systems at various salt concentrations.