Ethylene Oxide Groups Research Articles

Molecular dynamics simulations of nonionic surfactant adsorbed on subbituminous coal model surface based on XPS analysis

ABSTRACTA molecular dynamics (MD) simulation was conducted to study the adsorption behaviour of a nonionic surfactant adsorbed on low-rank coal. Owing to the complicated chemical component and structure of the coal surface, a modified graphite surface with hydroxyl, carboxyl, and carbonyl groups was utilised for a representation of the subbituminous coal surface model. The compositions of the hydroxyl, carbonyl, and carboxyl groups on the coal surface were found to be at a proportion of 25:3:5 according to the X-ray photoelectron spectroscopy (XPS) results. The interaction of nonylphenol ethoxylate with 8 ethylene oxide groups (NPEO-8) using this coal model in an aqueous phase was then simulated. It was revealed that the nonionic surfactant molecules were adsorbed at the interface between water and coal. This agminated structure of the surfactant molecules on the surface of the coal demonstrated an attachment of the surfactant ethoxylate groups to these solid surfaces and an extension of the remaining hydrophobic portions into the solution. Therefore, a coal surface with greater hydrophobicity was created. The dynamic properties of the water molecules characterised through self-diffusion coefficients indicate greater water mobility resulting from the existence of NPEO-8.

A Statistical Associating Fluid Theory Perspective of the Modeling of Compounds Containing Ethylene Oxide Groups

Compounds containing ethylene oxide groups as a repeating unit, such as glycols and their ethers, have several applications across different industrial fields. For efficient simulation, design, and optimization of industrial processes based on these compounds, reliable and robust thermodynamic models able to accurately describe their phase equilibria and thermophysical properties are required. For the choice of thermodynamic models available in the literature, the selection of the most adequate is not always obvious, but results have shown overtime that, for associating or polar fluids, association models derived from the statistical associating fluid theory are more accurate and physically sound than the cubic equations of state widely used by industry. However, the current modeling approaches used within the framework of association models have known limitations that must be understood by those developing and applying these models as they often result in a loss of accuracy and extrapolative or predictiv...

Novel open-chain crown ether bridged diphosphates as chelating ligands for lanthanides extraction in supercritical carbon dioxide

A series of highly CO2-soluble open-chain crown ether bridged diphosphates were designed and prepared as chelating ligands which were used to extract lanthanide ions from cellulose paper into supercritical CO2 (ScCO2). These ligands were designed by introducing different ester side chains and joining the two phosphorus groups with different length of ethylene oxide group which could provide enhanced solubility and complexation ability. The solubility data of these synthesized diphosophates in ScCO2 were measured at 313.15 K and 10.65 MPa–13.69 MPa. Lanthanides metal ions including La3+, Ce3+, Pr3+, Nd3+, Sm3+, Gd3+, Er3+, and Yb3+ were successfully removed from the solid matrix by supercritical fluid extractions using these chelating ligands at 313.15 K and 20 MPa. The extraction efficiency of metal ion was affected by chelating ligands’ side chain, which increased from 68% to 94% mainly driven by the increased solubility capability.

On the Relationships between the Hydrophilic–Lipophilic Balance and the Nanoarchitecture of Nonionic Surfactant Systems

AbstractBuilding links between established parameters for the characterization of surfactant systems is useful not only for the understanding of the underlying phenomena but also for the judicious formulation of products. Herein, we review comprehensively the literature data to find correlations between the hydrophilic–lipophilic balance (HLB) and the molecular packing parameter (CPP) for a variety of nonionic surfactants in water. The interfacial area per surfactant molecule, a fundamental variable to calculate CPP, follows a power law as a function of the number of ethylene oxide (EO) groups in the surfactant. The exponent ranges from 0.3 to 0.7, which may reflect changes in the conformation of the EO chain depending on the nature of the hydrophobic group; there is also apparently a transition toward a collapsed conformation of the EO chains at high surfactant concentrations. CPP is found to change linearly with HLB in the range of data studied, although the parameters of the linear fitting depend on the nature of both hydrophobic and hydrophilic moieties of the surfactant; this would also imply a linear relationship between CPP and the HLB temperature (i.e., Phase Inversion Temperature) according to the Kunieda–Shinoda equation. Analysis of the liquid crystal regions of the surfactant phase diagram at constant temperature indicates that the HLB values required for the morphological phase transitions defined by CPP increase with surfactant concentration. The present report may serve as a contribution to the programmed design of nanoarchitectures in surfactant systems.

The effect of ethylene oxide groups in dodecyl ethoxyl ethers on low rank coal flotation: An experimental study and simulation

To study the effects of ethylene oxide (EO) number in surfactants on low rank coal (LRC) flotation, dodecyl ethoxyl ethers (C12EOn) with three different EO numbers were selected and their adsorption and flotation behaviors were experimentally investigated. The results show that all C12EOn can obtain the same maximum flotation recovery. Increasing the number of EO in C12EOn lowers the necessary amount of reagent. Greater selectivity can be achieved with increasing EO number in C12EOn. Furthermore, the surface model of LRC (organic matter) and kaolinite (representative of mineral matter) was constructed, and the adsorption behavior of C12EOn on the LRC surface was analyzed based on the adsorption configuration, interaction energy, hydrogen bond interaction and surface areas. The calculated results show that increasing the EO number in C12EOn could accelerate the interaction between LRC and C12EOn at low surfactant concentrations. Since the same chemical structure of C12EOn, increasing the EO number does not make any significant difference in their interaction when the surfactant concentration is high. A combined theoretical approach [density functional theory (DFT) calculations and molecular dynamics simulations (MD)] was adopted to investigate the microscopic mechanism of the increase in LRC hydrophobicity by C12EOn adsorption. Finally, the competitive adsorption of C12EOn between organic matter and kaolinite was studied. The research results indicate that the selectivity is higher with increasing EO number in C12EOn, which is consistent with the experimental results. The microscopic mechanism of EO groups in surfactants on LRC flotation discussed in this study may have potential use in surfactant design and selection.

Influence of Temperature on the Surface Tension of Triton Surfactant Solutions

AbstractThe surface tension of different Triton surfactants (X‐100, X‐405, and X‐705) with or without adding sodium chloride was measured in the temperature range between 20 and 40°C using the maximum bubble pressure method. Rising temperature reduced the surface tension of Triton surfactants via disrupting the H‐bonds between the ethylene oxide (EO) group and water. Increasing the number of the EO groups created the steeper thermal gradient of the surface tension. The data indicated that EO‐water bonds are easier to be broken by rising temperature than the water–water H‐bonds, with an entropy change of −0.535 J deg−1 per mole of EO. The presence of NaCl decreased the surface tension for all systems. However, NaCl produced a synergistic effect with surfactants on the surface tension.

Synthesis and Characterization of Novel Surfactants based on 2‐Hydroxy‐4‐(Methylthio)Butanoic Acid Part 3: Microemulsions from Nonionic Sulfoxide Ester Surfactants

AbstractIn this work, ester sulfoxide (ESO) surfactants based on 2‐hydroxy‐4‐(methylthio) butyric acid are shown to have temperature‐sensitive microemulsion phase behaviors. Both C10 (C10ESO) and C12 (C12ESO) surfactants studied contained one sulfoxide unit in the structure. Phase inversion temperatures (PIT) and interfacial tensions (IFT) between water‐rich and oil‐rich phases have been measured for ternary systems of water, oil, and sulfoxide surfactants. Hydrophilic–lipophilic deviation (HLD) parameters of these surfactants were obtained by fitting the experimental data to a semiempirical HLD equation. The characteristic surfactant parameter and temperature sensitivity of C10ESO and C12ESO surfactants were obtained and compared with similar ethoxylated alcohol surfactants. By comparing the characteristic parameters of these surfactants with those of ethoxylated alcohol surfactants, it was shown that one sulfoxide ester moiety is equally hydrophilic as approximately 5 ethylene oxide groups. The temperature sensitivity of the ESO was roughly a factor of four less than ethoxylated surfactants based on the temperature coefficient of the HLD equation.

Prediction of microemulsion phase behavior from surfactant and co-solvent structures

A predictive model was developed that captures quantitative structure-property relationships between the molecular structures of surfactants and co-solvents and microemulsion phase behavior. Both the optimum salinity and the optimum solubilization ratio (and thus the interfacial tension) are modeled as a function of both monovalent and divalent cations in the brines. A dataset consisting of 685 microemulsion phase behavior experiments with 24 unique crude oils, 85 surfactants (internal olefin sulfonates, alkylbenzene sulfonates, alcohol alkoxy sulfates and alcohol alkoxy carboxylates) and 18 co-solvents (alcohols and alcohol alkoxylates) was used for the model development and validation. Variations in the type of hydrophobe (carbon number, degree of branching, polydispersity, and aromaticity), number of propylene oxide groups, number of ethylene oxide groups, and the type of head group (sulfonate, benzene sulfonate, sulfate, carboxylate, hydroxyl) were studied. The oils were characterized using their equivalent alkane carbon number. The model includes the effect of soaps generated from the neutralization of acidic crude oils. The interfacial concentration of co-solvent is calculated using the pseudophase model. Previous models for optimum salinity have not included the effects of divalent cations, soap, and co-solvents among other limitations. Most importantly, the new model can be used to predict interfacial tension as well as optimum salinity and provide a better understanding of the impact of molecular structures on microemulsion phase behavior. The model is sufficiently accurate to provide a useful guide to experimental testing programs for the development of chemical formulations for enhanced oil recovery and other similar applications requiring low interfacial tension.

Oligo(ethylene oxide) chains in fluorene bridge units of perylenediimide dimers as an efficient strategy for improving the photovoltaic performance in organic solar cells

Perylenediimides (PDIs) are among the most promising non-fullerene electron-acceptors for applications in organic photovoltaics (PV), providing a large scope for structural modifications. PDI-based dimers have shown the highest performances in PV devices owing to their characteristic twisted conformations that reduce their tendency to form large aggregates which are detrimental for PV operation. In this work, two fluorene-bridged perylenediimide (PDI) dimers with oligo(ethylene oxide) or alkyl chains anchored to the C9 position of the fluorene unit were synthesized and investigated in solution-processed organic bulk heterojunction (BHJ) photovoltaic cells as electron acceptors. The PDI dimer substituted with oligo(ethylene oxide) chains resulted in improved power conversion efficiencies (in 20%–53%) in solution processed bulk heterojunction (BHJ) cells with two different polymer donors, PTB7 and PffBT4T-2OD. Nevertheless, the replacement of alkyl chains by oligo(ethylene oxide) chains did not significantly affect the geometric characteristics of the PDI dimers and the optical and electrochemical properties were only marginally modified. Increased exciton dissociation and enhanced charge transport derived from a more densely packed π-π stacking in the solid state caused by ethylene oxide groups are pointed out as possible causes for the improved PV performance. The influence of 1,8-diiodooctane as solvent additive in the blend films was also investigated and allowed to further increase the efficiencies of the cells with PTB7. Overall, the results show that the simple replacement of alkyl chains by oligo(ethylene oxide) chains in PDI dimers is an efficient way to improve the PV performance without compromising the optoelectronic properties of the PDI acceptor.

An AB alternating diblock single ion conducting polymer electrolyte membrane for all-solid-state lithium metal secondary batteries

Lithium 4,4′-difluorobenzene sulfonyl imide is copolymerized with polyethylene glycol (PEG, Mw = 200, 400, 600, 800 and 1000) to synthesize a series of AB alternating diblock copolymer electrolytes (ADCE-1, 2, 3, 4, 5) for reducing the crystallinity of solid-state single ion conducting materials for applications in all-solid-state lithium metal secondary batteries. The free-standing film of ADCE-5 with the highest [EO]/[Li+] ratio (23.7:1) is found to display the lowest glass transition temperature (Tg) and the highest ionic conductivities of 6.61 × 10−6 S cm−1 at 30 °C and 2.24 × 10−4 S cm−1 at 100 °C. The alternating architecture of the polymer effectively prevents the polymer from phase separation originated from aggregation of the ionic groups as well as the ethylene oxide groups. As a result, segment motion may take place readily in the amorphous region at low temperature. Subsequently, a piece of glass fiber mat reinforced composite polymer electrolyte film is prepared for practical battery tests. The fabricated all-solid-state single ion conducting polymeric lithium metal secondary battery is able to work at a temperature as low as 40 °C with stable cycling performance. The battery delivers 102 mA h g−1 at 0.1 C and is stabilized at 94 mA h g−1 after 200 cycles.

Oligomer-Specific, Short Chain Linear Alcohol Ethoxylate Quantification via Comprehensive Two-Dimensional Gas Chromatography

Non-ionic linear alcohol ethoxylated surfactants (LAEs) make up a broadly utilized class of compounds commonly employed in unconventional hydraulic fracturing activities. However, current detection and quantification methods fail to operate in relevant concentration ranges and are limited in specificity because of a lack of access to all analytical standards for individual LAE oligomers. Here, we present a novel extraction and quantification technique for aqueous samples containing both petroleum hydrocarbons and short chain LAEs with alkyl chain lengths of 6–10 carbons and 0–9 ethylene oxide groups. Using liquid–liquid extraction and two-dimensional gas chromatography with flame ionization detection, the method provided over 80 and 100% recovery of LAEs and n-alkane hydrocarbons, respectively. Individual LAE oligomers were quantified using calibration curves of n-alkanes and adjusted response factors based on the effective carbon number (ECN) concept, and we present a detailed framework for calculating E...

Influence of Hydrophilicity on the Thermal-Driven Surfactant Flow at the Air/Water Surface.

A series of Triton surfactants with increasing number of ethylene oxide (EO) groups were applied to investigate thermal-driven surface flow. It was found that the thermal gradient is proportional to the number of EO groups on the surface. This correlation leads to the linear correlation between the surfactant structure and the driving force of the surface flow. The friction force, in contrast, follows a monotonic but nonlinear correlation with surfactant’s EO groups. The results demonstrate the possibilities to manipulate the surface flow, with potential applications in multiple-phase systems.

Cleaning Efficiency of Amino-Acid Surfactants with Polyoxyethylene Ether and Isopropanol in Liquid Carbon Dioxide

Although anionic surfactants have a distinct positive influence on the removal of particulate soil, the removal of particulate soils is insufficient in CO2 compared to perchloroethylene. A series of amino-acid surfactants was selected as main surfactants to study the influence of polyoxyethylene ether and cosolvent on the cleaning effect. Glu-C12 and C16(3) gave the best cleaning results, which increased from a detergency value of 4.6 when no surfactants were used to 8.32 when surfactants were used. In all experiments, charged anionic surfactant particles were formed, which are responsible for the removal of particulate soil from fabric by electrostatic repulsion. The use of a cosolvent (Isopropanol [IPA]) had a positive effect on the removal of particulate soil when using Glu-C12 and TX-45. However, for other compounding combinations, the addition of IPA had a negative effect on particulate soil removal. Of the cosolvents investigated, IPA was the most suitable. With the polarity of the system increasing after adding IPA, the ethylene oxide groups of TX-45 were partially extended to CO2. Through the steric effects of branched methyl groups, the cleaning effect was improved.

Synthesis and physiochemical properties of poly(ethylene glycol)-octanol sulfosuccinates

A series of sulfonated maleic diesters with ethylene oxide groups were synthesized by the reactions of esterification and sulfonation. Maleic diesters were prepared by esterification of maleic anhydride with any one kind of poly(ethylene glycol) with different molecular weights from 200 to 1000 and isooctanol, and then sulfonated by sodium bisulfite to get poly(ethylene glycol)-octanol sulfosuccinates. Reaction temperature and time of esterification of monoester and diester, using toluene sulfonic acid as catalyst and toluene as solvent, were investigated. The surfactants synthesized are identified by FTIR and 1HNMR. Thermal analysis results identify that the investigated surfactants have a good thermal stability. The surface activity of the surfactants in aqueous solution was determined at 298 K. It was found that the critical micelle concentrations (CMC) decrease with increase of the molecular weights and the number of ethylene oxide units of the investigated products, surface tension values at the CMC (γCMC) are upward trend in general. The maximum surface excess concentration (Γmax) decreases mildly with the increasing of molecular weight of poly(ethylene glycol), and area per molecule (Amin) increases with the increasing of ethoxy chain unit. Hydrodynamic diameter of investigated surfactants increases with increasing the concentration, and decreases in general trend with increase of molecular weight of poly(ethylene glycol). Addition of salt to the aqueous solution of surfactants sharply decrease values of CMC and γCMC compared with corresponded surfactants in distilled water.

Laboratory investigation of oil recovery by CO2 foam in a fractured carbonate reservoir using CO2-Soluble surfactants

Miscible CO2 flooding has been used as an EOR method for carbonate reservoirs which hold around 60% of the world's oil reserves. However, natural fractures, unfavorable mobility ratio and gravity segregation in carbonate reservoirs often lead to premature CO2 breakthrough and bypassed oil. To remedy this situation, CO2 foam has been used to reduce the mobility of the injected CO2. Typically, this employed a water soluble surfactant for foam propagation. However, surfactant transport in the aqueous phase was often hindered by surfactant adsorption and undesirable chemical reactions with reservoir minerals. In this study, we investigated whether CO2-soluble surfactants were more effective than water-soluble surfactant in oil recovery of fractured carbonate reservoirs under miscible conditions.A series of corefloods were conducted to determine the oil recovery factor (RF), speed of foam propagation and foam strength in artificially fractured carbonate cores at 35 °C (308.15 K) and 1500 psi (1.034*107 Pa) which was above minimum miscibility pressure. Silurian Dolomite outcrop with permeability of 150 md and West Texas Wasson crude were used. The cores were intermediate-wet indicated by both qualitative and quantitative tests. Three different surfactants were compared including an anionic water-soluble surfactant and other two nonionic CO2 soluble surfactants (2-ethyl-1-hexanol with different ethylene oxide groups) with distinct degree of solubility in CO2. Phase behavior experiments indicated these surfactants did not lower the interfacial tension significantly between the crude and water.RF of CO2 flooding was only 24% due to the heterogeneous nature of the fractured core. Co-injection of CO2 and water increased the RF to 35%, which was further increased to 54% when a water-soluble only surfactant presented. However, use of CO2 foam by the two CO2-soluble surfactants increased the RF to 71% and 92% respectively, with a higher RF for the surfactant that partitioned more to the CO2 phase. Also, pressure drop in different sections of the core confirmed that the surfactant which partitioned more into the CO2 phase gave a faster-propagating and stronger foam.These results educated that the partitioning of surfactant into the CO2 phase has several advantages. First, it allows surfactant to be transported in the CO2 phase ahead of the aqueous phase thus leading to faster foam propagation. Second, it generated a stronger foam. The combined effect of the two leaded to higher RF in current scenarios. Several hypotheses based on literature were raised and listed to further interpret the observations. Our results also reinforce that the so-called optimal CO2 soluble surfactant is case dependent and is the function of injection strategy, reservoir environment, and operation pressure or rates as well as other specific conditions. One could tailor a surfactant with suitable solubility in the CO2 phase to optimize oil recovery in fractured carbonates. We believed the results were encouraging enough to warrant further R&D and eventual field piloting.

Phase equilibria and the surface tension of polypropylene polyol series in water/methanol mixtures: A consideration of structural effects

The phase equilibria and surface tension of a polypropylene polyol (PPP) series was studied in aqueous solvent systems. The PPP series was composed of ethylene oxide (EO) and propylene oxide (PO) groups, exhibiting specific interactions with both water and alcohols. Binary and ternary liquid-liquid equilibria (LLE) of the PPP series were determined via thermo-optical analysis (TOA) methods, which represented closed-loop miscibility in water and Treybal Type 1 behavior in water and methanol (MeOH), respectively. The surface tension of the ternary PPP1/water/MeOH system was measured using a well-known plate method. The dendritic characteristics of the PPP series were reflected through modeling using lattice cluster theory (LCT) for complex structures of the polymer. The phase diagrams and surface tension of the PPP series were described from binary to ternary systems based on LCT incorporated with Guggenheim's treatment using predetermined parameters. The calculated results of both systems were in good agreement with the experimental data using the same interaction energy parameters.

Molecular dynamics simulations and contact angle of surfactant at the coal–water interface

Wettability of nonylphenol ethoxylate with four ethylene oxide groups (NP-4) on a subbituminous coal was carried out. As the concentration of NP-4 gradually increases, the contact angle firstly increases and then decreases with maximum contact angle at about critical micelle concentration (CMC) of NP-4. The monolayer adsorption behaviour of NP-4 on the model surface of Hatcher subbituminous coal was investigated by means of molecular dynamics simulations. The surfactant molecules could be detected at the water–coal interface. The water molecules are repelled and stronger hydrophobicity of the coal is obtained in the presence of NP-4, which are consistent with contact angle results at low concentration. The aggregated structure of the surfactant molecules on the coal surface in terms of head group and tail group density profiles along the perpendicular direction shows that the ethoxylate groups of the surfactant are attached at the solid surfaces. The negative interaction energy between NP-4 and the subbituminous coal surface calculated suggests that adsorption process is spontaneous. The self-diffusion coefficients results indicate that the presence of NP-4 causes higher water mobility meaning improving the hydrophobicity of low-rank coal, which is consistent with the experimental results of contact angle.

Poly(ethylene oxide carbonates) solid polymer electrolytes for lithium batteries

Poly(ethylene oxide) (PEO) is the gold standard matrix for polymer electrolytes used in actual all-solid lithium batteries. However, PEO solid polymer electrolytes show some limitations; such as relatively low ionic conductivity and lithium transference number resulting in the actual polymer-lithium batteries operating at 70 °C. In the last years, polycarbonates (PC) have been presented as an alternative polymer matrix with superior ionic conductivity for solid batteries which may work at room temperature. In this article we systematically investigated the properties of new polymers which combine varying composition of both ethylene oxide and carbonate groups. A series of poly(ethylene oxide carbonates) (PEO-PCs) have been synthesized by polycondensation between different ethylene oxide diols and dimethyl carbonate. As a result, eight new PEO-PCs with number of ethylene oxide units ranging from 2 to 45 between carbonate groups were synthesized and characterized in terms of physico-chemical properties (Tm and Tg). These PEO2-45-PC were formulated as solid polymer electrolytes (SPE) by adding different amounts of bis(trifluoromethane)sulfonimide lithium salt. The effect of the SPE composition (ethylene oxide/carbonate ratio, salt content) on the ionic conductivity and thermal properties (glass transition temperature and melting temperature) was investigated. The optimum SPEs showing the lowest glass transition temperature led to highest ionic conductivity value of 3.7·10−5 S cm−1 at room temperature. FTIR spectra revealed the coordination between the carbonate groups in the polymer chain and the lithium salt. 7Li-19F NMR analysis T1 relaxation and diffusion coefficients measurements indicated local dynamics that correlates with the general conductivity behaviour.

Micellar interaction of binary mixtures of alpha olefin sulfonate and nonylphenol polyethylene glycol ethers: Length effects of ethylene oxide

The micellization behavior of binary surfactant mixtures constituted by an anionic surfactant, alpha olefin sulfonate (AOS), and a nonionic surfactant nonylphenol polyethylene glycol ether (NPE) with different numbers of ethylene oxide (EO), namely, NP10EO, NP20EO, NP30EO, and NP40EO was comprehensively investigated by surface tensiometer, conductometer, cloud point measurement, and dynamic light scattering. Theoretical treatments were carried out to explain molecular interaction in the mixed micelles based on regular solution theory of Rubingh, micellization thermodynamics of Molyneux et al. and Maeda, and molecular thermodynamic theory of Pavvada and Blankschtein. Results indicate non-ideal mixing behavior in all AOS-NPE mixtures, where nonionic surfactant EO chain length was found to play critical roles. In the absence of additional electrolytes, NPEs exhibited substantially higher activity in micelles than bulk solution; with growth of EO groups, shrinkage on the scale of synergistic interaction was evidenced. In contrary, with swamping amount of electrolytes, synergistic interactions enlarged with the rise of EO groups, and AOS activity in mixed micelles was found depending on both EO length and bulk mole fraction (αA). These findings are of great significance in mixed surfactant formulation design/optimization to maximize the synergistic efficiency of the system thus to minimize the chemical consumption and cost.

Boosting Effect of Amphiphilic Random Copolymers for Bicontinuous Phases.

Amphiphilic random copolymers, poly(oxyethylene)/poly(oxypropylene) butyl ethers (C4EmPn), have been used as raw materials for cosmetics. This paper reports on the influence of amphiphilic random copolymers on mixtures of n-decane, water, and a nonionic surfactant, hexa(oxyethylene) dodecyl ether (C12E6). Bicontinuous phases are formed from decane/water/C12E6 mixtures at high C12E6 weight fractions (> 70 wt%). Adding C4EmPn to decane/water/C12E6 mixtures brings about the formation of bicontinuous phases and a decrease in the amount of the surfactant required for their formation, indicating efficiency boosting. The bicontinuous phase formation region in the phase diagram of the decane/water/C12E6+C4E5P5 system is largest at a specific C4E5P5 weight fraction in the C12E6/C4E5P5 mixture. When a hydrophobic polymer, in which the poly(ethylene oxide) group in C4EmPn is absent, is added to decane/water/C12E6 mixtures, no efficiency boosting is observed. These results suggest that the adjustment of the hydrophilicity-hydrophobicity balance of C12E6/C4EmPn mixture causes the efficiency boosting.