Formation Of Mixed Micelles Research Articles

High efficacy of chloroquine-derived bile salts in Pluronic F127 micelles against blood-stage Plasmodium falciparum

Colloidal nanocarriers can play a key role in the efficacious delivery of drugs, including antimalarials. Here, we investigated the ability of polymeric micelles of the block copolymer F127 to act as nanovehicles for two organic salts derived from chloroquine and human bile acids, namely, chloroquinium cholate (iCQP1) and chloroquinium glycocholate (iCQP1g). We have previously reported the strong in vitro antiplasmodial activity of these salts, which displayed IC50 values of 13 and 15 nM against blood forms of Plasmodium falciparum, respectively. By deriving from amphiphilic lipids, iCQP1 and iCQP1g also enclose the ability to act as surface-active ionic liquids (SAILs). The micellization properties of neat F127 and of the F127/SAIL mixtures were initially investigated to gain physicochemical insight into the interaction between polymer and bioactive SAILs, resorting to differential scanning calorimetry, surface tension measurements and dynamic light scattering. Micelle formation by F127 is an endothermic process strongly temperature and concentration dependent. Interestingly, this process is significantly changed when the molar fraction of SAIL (xSAIL) in the F127/SAIL mixture is varied between 0.33 and 0.90. Both SAILs favor the formation of mixed micelles by decreasing the micellization temperature, and (observed only when for xSAIL = 0.33) by synergistically decreasing the cmc. Concomitantly, the micellar size is reduced from 18 to 13 nm as xSAIL is increased from 0.33 to 0.90. Crucially, in vitro assays show that when the SAILs are loaded into F127 polymeric micelles, their antiplasmodial efficacy is substantially enhanced, with a significant drop in IC50, especially for the iCQP1/F127 system. This opens new possibilities for the nanoformulations of antimalarial compounds.

Self-assembly of mixed surfactants sodium dodecylsulfate and polyethylene glycol dodecyl ether in aqueous solutions

The thermodynamic behavior of mixed systems containing the anionic surfactant sodium dodecyl sulfate (SDS) and the nonionic surfactant polyethylene glycol dodecyl ether (Brij L4) in aqueous solutions was investigated. Electrical conductivity and interfacial tension measurements were employed to investigate the concentration-dependent properties of these surfactant mixtures. Two main experiments were conducted: i) constant ratio experiment: the overall surfactant concentration was varied while maintaining a fixed ratio between SDS and Brij L4. It was shown that the critical micelle concentration (CMC) determined from electrical conductivity measurements does not indicate the formation of the first mixed micelles as observed using tensiometry, but the point from which the adsorption of counterions by the existing micelles became important. By using the Regular Solution Theory (RST), it was found that the interaction between SDS and Brij L4 is synergistic, driven by dipole-ion interactions of the hydrophilic regions of the two surfactants. ii) Fixed SDS concentration while increase the Brij L4 concentration: the resulting electrical conductivity exhibited non-trivial behavior which complexity arose from simultaneous phenomena of incorporation of free SDS molecules into the micelles as Brij L4 concentration increased, leading to a decrease in electrical conductivity; liberation of some adsorbed counterions from the mixed micelles to the solution, which increases the conductivity and increase of viscosity due to Brij L4 further addition that leads to a sequential decrease in electrical conductivity.

Mixed Micellar Gel of Poloxamer Mixture for Improved Solubilization of Poorly Water-Soluble Ibuprofen and Use as Thermosensitive In Situ Gel.

The aqueous solution of binary mixtures of amphiphilic copolymers is a potential platform for fabricating mixed polymeric micelles for pharmaceutical applications, particularly in developing drug delivery depots for a poorly water-soluble compound. This study fabricated and investigated binary mixtures of poloxamer 403 (P403) and poloxamer 407 (P407) at varying P403:P407 molar ratios to develop a vehicle for the poorly water-soluble compound, using ibuprofen as a model drug. The cooperative formation of mixed micelles was obtained, and the solubility of ibuprofen in the binary mixtures was enhanced compared to the solubility in pure water and an aqueous single P407 solution. The binary mixture with the P403:P407 molar ratio of 0.75:0.25 at a total polymer concentration of 19% w/v exhibited the temperature dependence of micellization and sol-to-gel characteristics of the thermosensitive mixed micellar gels. It possessed suitable micellization and gelation characteristics for in situ gelling systems. The release of ibuprofen from the thermosensitive mixed micellar depots was sustained through a diffusion-controlled mechanism. The findings can aid in formulating binary mixtures of P403 and P407 to achieve the desired properties of mixed micelles and micellar gels.

Remediation of oil-polluted soil using anionic and non-ionic composite biosurfactants

ABSTRACT Petroleum hydrocarbons as pervasive pollutants pose a significant threat to soil ecology and human health. Surfactant washing as an established technique can effectively remediate soils contaminated by hydrocarbons. Biosurfactants, which combine the properties of surfactants and environmental compatibility, have attracted increasing interest. However, due to the high production cost of biosurfactants, their practical application is restricted. This study addressed these limitations by selecting two biosurfactants, β-cyclodextrin (C1) and sodium carboxymethyl cellulose (C2), and developed a promising cleaning agent formula through compounding and the addition of suitable additives. When the volume ratio of C1 to C2 was 8:2 and an 8 g/L mixture of sodium humate and sodium carbonate electrolyte was added, the surfactant system’s surface tension reached a minimum, yielding optimal oil removal. The formation and synergistic behaviour of mixed micelles of surfactants were explained using ideal solution theory and the Rubingh model. By optimising the oil washing process parameters – normal temperature of 25 °C, pH 11, washing time of 2 h, solid–liquid ratio of 1:5, and oscillation frequency of 200 r/min – the oil removal rate achieved 76%. This cleaning agent, characterised by low production cost, straightforward application, environmental compatibility, and rapid, significant cleaning effect, shows potential for field-scale purification of petroleum-contaminated soil.

Exploration of the effect of NaCl/urea on aggregation process of imipramine hydrochloride drug and TX-165 mixture: A surface tension and UV–visible study

In this research, mixed micellization analysis of imipramine hydrochloride (IMP), an antidepressant drug with nonionic TX-165 surfactant has been investigated entirely via tensiometry and UV–visible techniques. Influence of distinct solvents of certain concentration (aqueous/50 mmol.kg−1 NaCl/500 mmol.kg−1 urea) was also detected on mixed association behavior of IMP+TX-165 mixtures. As compared to the aqueous system, higher nonideality in IMP+TX-165 in NaCl solution was detected while in the urea system was found less i.e., the interaction between IMP and TX-165 in different solvents was found as follows: NaCl > aqueous > urea. The fraction of TX-165 in mixed micelles (X1m) was found to be higher than IMP caused by the high hydrophobicity of TX-165 than IMP. The attained interaction parameter (βm) for bulk mixed systems was negative in each case depicting the synergism or attractive interaction amid IMP and TX-165. Numerous evaluated thermodynamic parameters demonstrated that IMP+TX-165 mixed micelles formation is viable along with spontaneous and among all employed solvents, spontaneity was found higher in NaCl solvent and lower in urea solvent than aqueous solution. Interaction of IMP with TX-165 was also detected by UV–visible analysis as an increase in absorbance was attained. Overall, results might be helpful in the development of the drug delivery system.

The Effect of Lysophospholipids and Sex on Growth Performance and Small Intestine Morphology in Weanling Pigs, 7-30 kg.

Inclusion of lysophospholipids (LPL) has been proposed to increase growth performance in broilers and pigs, acting as emulsifiers through mixed micelle formation. The aim of this study was to investigate the effect of feeding LPL in weanling pig diets on growth performance and intestinal morphology. Eight hundred pigs (weight 6.96 kg ± SD 1.58 kg) were assigned to one of two dietary treatments, i.e., a basal diet (CON) or a basal diet + 0.05% lysophospholipids (LPL). The experimental period lasted for 42 days, and on days 40 and 41, 32 pigs in total were euthanized for intestinal tissue samples. From days 14 to 21, feed intake and average daily gain increased, as well as FCR, from days 28 to 42, in the LPL group compared with the CON group. In the overall period, no differences in growth performance were present between the groups. However, females displayed increased ADG from days 21 to 28 compared with castrates. The villous height tended (p = 0.051) to be lower in LPL in the proximal jejunum compared with CON. In the proximal jejunum, villus was higher (p > 0.01) in females, and in the distal jejunum, higher crypt cell proliferation (p < 0.01) and a tendency to deeper crypts (p = 0.064) were observed in female pigs as well. In conclusion, lysophospholipids did not increase growth performance in this study; however, the rate of recovery from a poorer starting point was noted, as growth rates recovered and increased faster in the LPL group. In conclusion, unlike the first phase, the LPL group recovered the growth from days 14 to 21 through higher feed intake and weight gain than the CON group. Eventually, the LPL group displayed improved FCR compared with the CON group from days 28 to 42. Further studies are needed to investigate whether this effect continues into the grower-finisher phase.

Exploring the Specific Role of Iron Center in the Catalytic Activity of Human Serum Transferrin: CTAB-Induced Conformational Changes and Sequestration by Mixed Micelles.

Conformational changes play a seminal role in modulating the activity of proteins. This concept becomes all the more relevant in the context of metalloproteins, owing to the formation of specific conformation(s) induced by internal perturbations (like a change in pH, ligand binding, or receptor binding), which may carry out the binding and release of the metal ion/ions from the metal binding center of the protein. Herein, we investigated the conformational changes of an iron-binding protein, monoferric human serum transferrin (Fe-hTF), using several spectroscopic approaches. We could reversibly tune the cetyltrimethylammonium bromide (CTAB)-induced conformation of the protein, exploiting the concept of mixed micelles formed by three sequestrating agents: (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate) hydrate (CHAPS) and two bile salts, namely, sodium cholate (NaC) and sodium deoxycholate (NaDC). The formation of mixed micelles between CTAB and these reagents (CHAPS/NaC/NaDC) results in the sequestration of CTAB molecules from the protein environment and aids the protein in reattaining its native-like structure. However, the guanidinium hydrochloride-induced denatured Fe-hTF did not acquire its native-like structure using these sequestrating agents, which substantiates the exclusive role of mixed micelles in the present study. Apart from this, we found that the conformation of transferrin (adopted in the presence of CTAB) displays pronounced esterase-like activity toward the para-nitrophenyl acetate (PNPA) substrate as compared to native transferrin. We also outlined the impact of the iron center and amino acids surrounding the iron center on the effective catalytic activity in the CTAB medium. We estimated ∼3 times higher specific catalytic efficiency for the iron-depleted Apo-hTF compared to the fully iron-saturated Fe2-hTF in the presence of CTAB.

NMR Study of Water-Soluble Carotenoid Crocin: Formation of Mixed Micelles, Interaction with Lipid Membrane and Antioxidant Activity.

Crocin is a unique water-soluble carotenoid found in crocus and gardenia flowers. Crocin has been shown to have a variety of pharmacological activities, such as antioxidant, anti-cancer, memory improvement, antidepressant, anti-ischemia, blood pressure lowering and aphrodisiac, gene protection and detoxification activities. Due to their amphiphilicity, crocin molecules form concentration-dependent self-associates (micelles) in a water solution. In the present study, using various NMR techniques (T2 relaxation and selective gradient NOESY), we have demonstrated that crocin forms mixed micelles with water-soluble drug delivery system glycyrrhizin and linoleic acid molecules. Note, that the spin-spin T2 relaxation time and NOESY spectroscopy are very sensitive to intermolecular interactions and molecular diffusion mobility. The second purpose of this work was the elucidation of the interaction of crocin with a model lipid membrane using NMR techniques and a molecular dynamics simulation and its effects on lipid oxidation. It was shown that the crocin molecule is located near the surface of the lipid bilayer and effectively protects lipids from oxidation by peroxyl radicals. The role of glycyrrhizin and vitamin C in metal-induced lipid oxidation was also elucidated. The results of this study may be useful for expanding the field of application of crocin in medicine and in the food industry.

Scrutinizing micellar transitions and interfacial properties in mixed micelles comprising sodium dodecyl sulfate and sodium oleate: A tensiometric and scattering insight

Mixed micellar systems play a pivotal role in numerous scientific and industrial applications due to their inimitable solution properties and potential for enhancing solubilization and emulsification processes. The present study unveils the mixed micellization behavior of two anionically charged surfactants, sodium dodecyl sulfate (SDS) and sodium oleate (SO), in aqueous solutions through a combination of solution viscosity, tensiometric and small-angle neutron scattering (SANS) techniques. The dynamic changes in the interfacial properties of the mixed micellar system as a function of the SDS-to-SO ratio are evaluated from surface tension measurements. The results offer an insight into the formation of the stable mixed micelles with the alteration in the critical micelle concentration (CMC) as a function of the composition of both surfactants and the nature of the interaction. Surface tension data disclose the thermodynamic aspects of micelle formation and the influence of surfactant interactions on the surface activity of the system. Complementing the surface tension measurements, SANS analysis was conducted to clarify the structural aspects of the SDS-SO mixed micelles. SANS inferred the micellar size, shape, and aggregation number (Nagg), thereby shedding light on the nanoscale organization of the micellar aggregates in the aqueous solution. By combining SANS and surface tension data, a comprehensive understanding of the mixed micellization behavior of SDS and SO is achieved, addressing both interfacial and structural aspects. A computational simulation approach has also been employed to obtain the optimized parameters, which provide a better understanding of the correlation of SDS and SO molecular orbital energy levels. The results underscore the importance of surface tension and structural characterization techniques to comprehend the behavior of mixed micelles fully.

Study on the properties of branched-chain alkyl glycoside nonionic surfactant and anionic surfactant in a mixed system

Abstract The surface activity, intermolecular interactions and thermodynamic parameters of a mixture of a nonionic surfactant (branched-chain alkyl glycoside (IG-10)) and an anionic surfactant (alcohol ether carboxylic acid (90H)) were investigated and the wetting, emulsifying and foaming properties of the mixed system were also evaluated. The results show that there is a mutual attraction at the mixed micelles and gas/liquid interfaces formed by the two surfactants. The thermodynamic parameters show that the formation of mixed micelles from two different surfactants is a non-ideal process. In terms of application performance, the wetting ability and foaming properties of the mixed system showed good synergistic effects, with the wetting time of the mixed system being shorter than that of the two single surfactant systems and the foam stability being weaker than that of the single system. The best emulsifying capacity was obtained when the mass fraction of 90H was 50 %.

Interaction Parameters for the Formation of Mixed Micelles and Partitioning of Solutes in Them: A Review

When two or more surfactants are mixed, the critical micelle concentration and solubilization capability are changed, and a careful selection of the combination promotes the micelle formation and enhances the solubilizing capability. Thus, understanding the mechanism behind the phenomena is essential for controlling the physical properties of the mixed micelle. The interaction parameters β and B that describe the formation of mixed micelles and their partitioning of solutes, respectively, were proposed by Treiner four decades ago. In this work, data on the formation and partitioning in binary surfactant systems were collected. Although the data on the parameters β and B for polar solutes and theoretical development are still insufficient, the directions of research to acquire an in-depth understanding of the formation and partitioning of the mixed micelle are proposed.

Exploring the role of mixed micelles and promoters for alcohol oxidation: A green catalytic approach and insights into micellar chemistry

Oxidation of 1-butanol at 30 °C was carried out using chromic acid in an aqueous medium, employing pseudo 1st order reaction conditions. The resultant 1-butanal was isolated through fractional distillation. Surfactant micelles, acting as tiny templates or nano-reactors, play a vital role in generating nano-structured materials with desired attributes. These micelles have shown promise as effective catalysts, including mixed anionic-nonionic micelles like SDS-TX 100. In the pursuit of enhancing the rate of oxidation, micelle catalysts were tested in conjunction with various promoters. Astonishingly, these combinations displayed an impressive rate acceleration. To validate the products and interactions, comprehensive analyses were conducted using techniques such as IR, NMR, and UV. The formation of mixed micelles was also established through DLS analysis. Interestingly, among the catalytic paths, mixed micelles combined with 2, 2́-Bipyridine (Bpy) promoter exhibited the highest oxidation rate, overshadowing other combinations. Further insight was gained by observing the rate constants: kobs (SDS) > kobs (TX 100) and kobs (Phen) > kobs (Bpy) > kobs (PA) for promoted reactions in single micelle catalysis. For SDS micelles and mixed micelles, the order was kobs (Bpy) > kobs (Phen) > kobs (PA), whereas in TX 100 micelles, it was kobs (Phen) > kobs (Bpy) > kobs (PA).

Effect of glycerol on micellization of quasi-binary mixture of zwitterionic cocamidopropyl hydroxysultaine and cetyltrimethylammonium bromide in aqueous solution

The micellization behavior of quasi-binary mixture of zwitterionic cocamidopropyl hydroxysultaine (CAPHS) with cationic cetyltrimethylammonium bromide (CTAB) was investigated both in aqueous solution and in glycerol-water. Both the tensiometric and the conductive techniques were adopted to determine the critical micelle concentrations (cmc) of individual and mixed surfactants. In the framework of the regular solution theory and based on the pseudophase separation model, some micellization and thermodynamic parameters were estimated by the Rubingh’s and the Clint’s models. The results indicate that the nonideal mixing of CAPHS with CTAB and the synergistic interaction between them play vital roles on the reduction of mixed cmc, the amplitude of synergistic interaction depends on the composition of mixture and the presence of glycerol induces the increase in the individual and mixed cmc values and the change of the participation of CAPHS in mixed micelle with the composition in bulk solution. The electrostatic repulsion, the diversity of molecular conformation and the steric hindrance can account for the formation of mixed micelle and the difference in micellar composition. Thermodynamic parameters show that the entropy makes overwhelming contributions on the spontaneous process of micellization, the release of mixing heat makes the stable mixed micelle formed and the presence of glycerol makes for reducing the contribution of entropy and forming the more stable mixed micelle. These findings help with understanding the interaction behavior between two species and the effect of glycerol and further providing some information for the design of the related surfactant formulations.

A novel approach to mixed micelles formation: study the interactions between bis-quaternary ammonium salts and nonionic surfactant Triton X-100

Abstract This article focuses on the description of novel mixed system formulations of bis-quaternary ammonium salts (bis-QASs) and the nonionic surfactant Triton X-100 (TX-100). Measurements of surface tension (γ), foam stability, contact angle (CA) and cloud point (CP) were investigated at different ratios of the given compounds. The results indicated that changes in the structure of the bis-QASs amphiphilic cation, including the length of the alkyl spacer and the presence or absence of –OH groups, affected the adsorption and micellization. Furthermore, the elongation of the alkyl spacer in the bis-QASs structure affects the increase in the CP temperature. The research carried out shows the future potential of mixed combinations (bis-QASs and TX-100) to be used in industrial applications.

Monitoring galactolipid digestion and simultaneous changes in lipid-bile salt micellar organization by real-time NMR spectroscopy

The use of Nuclear Magnetic Resonance spectroscopy for studying lipid digestion in vitro most often consists of quantifying lipolysis products after they have been extracted from the reaction medium using organic solvents. However, the current sensitivity level of NMR spectrometers makes possible to avoid the extraction step and continuously quantify the lipids directly in the reaction medium. We used real-time 1H NMR spectroscopy and guinea pig pancreatic lipase-related protein 2 (GPLRP2) as biocatalyst to monitor in situ the lipolysis of monogalactosyl diacylglycerol (MGDG) in the form of mixed micelles with the bile salt sodium taurodeoxycholate (NaTDC). Residual substrate and lipolysis products (monogalactosyl monoacylglycerol (MGMG); monogalactosylglycerol (MGG) and octanoic acid (OA) were simultaneously quantified throughout the reaction thanks to specific proton resonances. Lipolysis was complete with the release of all MGDG fatty acids. These results were confirmed by thin layer chromatography (TLC) and densitometry after lipid extraction at different reaction times. Using diffusion-ordered NMR spectroscopy (DOSY), we could also estimate the diffusion coefficients of all the reaction compounds and deduce the hydrodynamic radius of the lipid aggregates in which they were present. It was shown that MGDG-NaTDC mixed micelles with an initial hydrodynamic radius rH of 7.3 ± 0.5 nm were changed into smaller micelles of NaTDC-MGDG-MGMG of 2.3 ± 0.5 nm in the course of the lipolysis reaction, and finally into NaTDC-OA mixed micelles (rH of 2.9 ± 0.5 nm) and water soluble MGG. These results provide a better understanding of the digestion of galactolipids by PLRP2, a process that leads to the complete micellar solubilisation of their fatty acids and renders their intestinal absorption possible.

Formulation and Evaluation of Mixed Micelles Containing Quercetin for Inhibiting Intestinal Metabolism of Atorvastatin

Atorvastatin is a poorly bioavailable drug due to fast-pass metabolism. The objective of the study was to prepare quercetin-containing mixed micelles for inhibiting intestinal metabolism of Atorvastatin. Mixed micelles of atorvastatin were prepared using the film hydration method and optimized the formulations were based on different ratios of poloxamer 188 and SDC. The drug permeation and permeability coefficients of mixed micelles were calculated from ex vivo study using goat intestine. To the optimized formulation (F7), quercetin was added to improve the permeability of Atorvastatin. The vesicle size, % entrapment efficiency, and % in vitro drug release of optimized formulation (F7) were found 273.11 nm, 91.34 % and 72.14 %, respectively. The ex vivo results of Atorvastatin with quercetin (25 mg) showed two times more permeation (flux = 2.69 µg/cm2h) and Atorvastatin mixed micelles with quercetin (25 mg) showed three times (flux = 4.33 µg/cm2h ) compared to Atorvastatin without quercetin (flux = 1.34 µg/cm2h). The improvement of Atorvastatin permeation in the form of mixed micelles may be due to the blockage of the p glycoprotein efflux pump in the presence of quercetin. Histopathology study indicated that the formulation changed the microenvironment of tissue when using mixed micelles compared to no significant changes that occurred during control tissue. Based on the obtained results, we can conclude that the mixed micelles containing Atorvastatin enhanced the permeability effect in the presence of quercetin compared to the plain formulation without quercetin.

Binding and occupancy properties of gabapentin in mixed surfactant systems

AbstractThis research highlights the efficacy of mixed micellar systems as an innovative chemical formulation for improving the binding properties of active pharmaceutical drugs. The formulations based on the mole fraction were utilized for preparing mixed micelles with anionic sodium dioctyl sulfosuccinate (AOT) and sodium dodecyl sulphate (SDS). DLS measurements demonstrated the formation of small micelles and mixed micelles in SDS‐AOT combinations. A UV absorbance investigation demonstrated the effectiveness of the SDS‐AOT mixed micelles for determining the binding constant (Kb) and mean ion occupancy (i0) of the anticonvulsant gabapentin (GBP) drug. Kb values increased, but the occupancy (i) of GBP per micelle decreased by decreasing the mole fraction (α) of SDS from αSDS 0.9 to 0.1, predicting a shift in occupancy of drugs from the Palisade to the Stern layer. To get a better comprehension of micellization behavior and preferential interaction of the drugs under study, molecular docking studies were performed. According to the docking studies, the GBP displayed significant binding in the presence of SDS‐AOT when compared to pure SDS and AOT molecules. Ultimately, in pharmaceutical applications, mixed micelle played an important role in enhancing the binding and encapsulation efficiency of drugs.

Synergistic interaction on quasi-binary mixture of amino sulfonate amphoteric surfactant with nonionic diethanolamide induced by glycerol and its concentration

Molecular interaction about a quasi-binary mixtures of an amino sulfonate surfactant, sodium 3-(N-dodecyl ethylenediamino)-2-hydroxypropyl sulfonate (DES), with a fatty acid diethanolamide derived from coconut oil (CDA) in aqueous solutions containing both the glycerol of 0.100 mol/L and 0.200 mol/L was investigated using the surface tension measurement. The interfacial parameters indicate that the mixing of DES with CDA can promote the formation of the more compact distribution of molecules adsorbed in the mixed monolayer, the mixing ratio of the mixture induces the difference in the adsorption behaviors at air–liquid interface, and the standard free energy of adsorption at air–liquid interface implies the benefit of adsorption and the change of adsorption behavior based on both the concentration of glycerol in solutions and the mixing ratio in the mixture. In the framework of pseudo-phase separation model, thermodynamic models including the Clint’s model, the Rubingh’s model and the Maeda’s model were employed to effectively estimate the related micellization and thermodynamic parameters. The nonideal mixing of DES with CDA and their synergistic interactions in the mixed micelle depend on both the mixing ratio of the mixture and the concentration of glycerol in solutions. The abundant amount of DES in mixed micelle will result in the absence of synergistic interaction in aqueous solutions containing the glycerol of 0.100 mol/L, and whereas the abnormal case does not again emerge on increasing the concentration of glycerol to 0.200 mol/L. The compatibility in molecular conformation, the steric hindrance, the electrostatic repulsion and the hydrogen-bond formation are adopted to theoretically explain the interaction behavior. Thermodynamic parameters obtained using the Maeda’s treatments also confirm the absence or the presence of synergistic interaction and the formation of stable mixed micelle. These findings will help with understanding the intermolecular behavior and the effect of alcohol concentration.

Interaction of saponification products of Robinia pseudoacacia seed oil with cetyltrimethyl ammonium bromide

AbstractThe interaction between novel saponification products (RCOONa or RCOOK) of Robinia pseudoacacia seed oil and cetyltrimethyl ammonium bromide (CTAB) in aqueous solution have been investigated by surface tension method at 25°C. The critical micelle concentration (cmc) of RCOONa/CTAB and RCOOK/CTAB mixture were measured. The surface properties of saponification products, CTAB as well as the mixed system were explored and compared. The composition, activity coefficient of mixed micelle, and the interaction parameters (βσ, βM) between surfactants were estimated according to the Regular Solution Theory, the Clint's model and the Rubingh's model in the framework of pseudophase separation model. The experimental results suggested that both RCOONa and RCOOK have synergism with CTAB in mixed micelle formation and surface tension reduction through calculating of βσ and βM in the mixed system. This could be attributed to the strong interaction between the head groups with opposite charges in the surfactant molecules.

PFAS-CTAB Complexation and Its Role on the Removal of PFAS from a Lab-Prepared Water and a Reverse Osmosis Reject Water Using a Plasma Reactor.

Electrical discharge plasma reactors with argon bubbling can effectively treat long-chain perfluoroalkyl acids (PFAAs) in contaminated water, and the addition of a cationic surfactant cetrimonium bromide (CTAB) is known to enhance the removal of short-chain PFAAs. However, the roles of PFAA chain length, functional group, and water matrix properties on PFAA-CTAB complexation are largely unknown. This work investigated the bulk liquid removal of different PFAAs by CTAB in the absence of plasma. Stepwise addition of CTAB was subsequently used to efficiently treat PFAAs in a lab-prepared water and a reverse osmosis (RO) reject water using an enhanced contact plasma reactor. The results show that CTAB inhibited the bulk liquid removal of long-chain PFAAs in the absence of plasma likely due to the formation of hydrophilic CTAB-PFAA mixed micelles and competition for interfacial access between long-chain PFAAs and CTAB. On the contrary, CTAB enhanced the removal of short- and ultrashort-chain PFAAs by forming hydrophobic complexes. After 6 h of treatment in the plasma reactor with CTAB, PFAAs were 86 to >99% removed from the lab-prepared water and 29 to >99% removed from the RO reject water. This study provides important insights for overcoming mass transfer limitations for PFAA treatment technologies.