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We conduct dissipative particle dynamics simulations of nonionic surfactant solutions to investigate the statistical properties of micellar recombination. We categorize the recombination events into self-recombination, where two micelles created by scission join together, and non-self-recombination. We find that these two recombination events exhibit distinct statistical properties. The probability density function of the recombination time for self-recombination follows a power law, and we show that the mean squared displacement of the surfactants determines the exponent of the power law. In contrast, the survival function for non-self-recombination is exponential, which is consistent with the mean-field model. For non-self-recombination, we evaluate the mean recombination time for various aggregation numbers, temperatures, and surfactant volume fractions. We find a scaling law describing the mean recombination time of the micelles at equilibrium. [ABSTRACT FROM AUTHOR]

The appraisal of drug–surfactant binding interactions is pharmacologically and pharmaceutically noteworthy. The simple model compounds of nucleic acids such as nucleic acid bases/nucleosides are key biologically active molecules useful for studying interactions of nucleic acids with other components in bio-fluids. Therefore, the binding studies of promethazine hydrochloride (PMT) drug with individual surfactants such as sodium dodecylsulphate (SDS, anionic surfactant), sodium lauroylsarcosinate (SLS, amino based-surfactant), and sodium cholate (NaC, trihydroxy bile salt), and their mixed systems (PMT + SDS/SLS/NaC) at mole fractions, αPMT = 0.02, 0.04, 0.06, and 0.08 have been accomplished in water and 0.025 mol kg−1 aqueous uridine (nucleoside) solutions at temperatures (298.15, 308.15, and 318.15) K. Thermodynamic characteristics of micellization have been obtained from the conductivity studies. Binding constants (Kb, Kf) and standard Gibbs free energies of binding (ΔGοb, ΔGοf) for pure PMT drug and its mixed systems with anionic surfactants were evaluated from UV–visible absorption and fluorescence emission studies. Further, the density functional theory (DFT) calculations for studied systems were carried out to get net stabilization energies for the drug–surfactant complexes. NBO and HOMO–LUMO analyses were also carried out in the absence/presence of uridine. Dynamic light scattering study was used to measure the hydrodynamic diameters in micellar systems. The major influences of hydrophobic–hydrophobic interactions among the hydrophobic groups and electrostatic (ionic and H-bond) interactions among the hydrophilic/ionic groups of PMT drug, SDS/SLS/NaC, and uridine have been depicted from the present investigations. [ABSTRACT FROM AUTHOR]

We develop a rheological model to approximate the nonlinear rheology of wormlike micelles using two constitutive models to represent a structural transition at high shear rates. The model is intended to describe the behavior of semidilute wormlike micellar solutions over a wide range of shear rates whose parameters can be determined mainly from small-amplitude equilibrium measurements. Length evolution equations are incorporated into reactive Rolie-Poly entangled-polymer rheology and dilute reactive-rod rheology, with a kinetic exchange between the two models. Although the micelle length is remarkably reduced during flow, surprisingly, we propose that they are not shortened by stress-enhanced breakage, which remains thermally driven. Instead, we hypothesize that stretching energy introduces a linear potential that decreases the rate of recombination and reduces the mean micelle length. This stress-hindered recombination approach accurately describes transient stress-growth upon start-up shear flow, and it predicts a transition of shear viscosity and alignment response observed at high shear rates. The proposed mechanism applies only when self-recombination occurs frequently. The effect of varying the relative rate of self-recombination on the rheology of wormlike micelles at high shear rates is yet to be explored. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cryo-electron tomography was used to determine the structural characteristics of complicated surfactant aggregates. • Transitions branched WLMs → saturated network of WLMs → perforated vesicles were observed in solutions of zwitterionic and nonionic surfactants. • Transformations proceed through an increase in the number of branches at the expense of cylindrical subchains and semispherical endcaps. • Exponential distribution of subchains length was confirmed experimentally for multiconnected saturated networks. • Perforated vesicles were observed when the length of subchains became much shorter than the persistence length. The formation of micellar aggregates and the changes in their morphology are crucial for numerous practical applications of surfactants. However, a proper structural characterization of complicated micellar nanostructures remains a challenge. This paper demonstrates the advances of cryo-electron tomography (cryo-ET) in revealing the structural characteristics that accompany the evolution of surfactant aggregates. By using cryo-ET in combination with cryo-transmission electron microscopy (cryo-TEM), small-angle neutron scattering (SANS), and rheometry, studies were carried out on a model system composed of zwitterionic and nonionic surfactants. In this system, the molecular packing parameter was increased gradually by increasing the molar fraction of nonionic surfactant. A series of structural transformations was observed: linear wormlike micelles (WLMs) → branched WLMs → saturated network of multiconnected WLMs → perforated vesicles (stomatosomes). The transformations occur through an increase in the number of branches at the expense of cylindrical subchains and semispherical endcaps. Exponential distribution of subchains length was confirmed experimentally for multiconnected saturated networks. The stomatosomes were formed when the length of subchains becomes much shorter than the persistence length, causing the three-dimensional (3D) structure to transform into a two-dimensional (2D) membrane. This work identifies the mechanism of the structural changes, which can be further used to design various surfactant self-assemblies. [ABSTRACT FROM AUTHOR]

The development of two eco-friendly analytical methods for the simultaneous determination of eight cardiovascular drugs; hydrochlorothiazide (HCT), captopril (CPL), lisinopril (LSP), valsartan (VAL), atorvastatin (ATR), bisoprolol (BSL), amlodipine (AML) and carvedilol (CVL); alongside with the nutraceutical vincamine (VIC) is essential for sustainable pharmaceutical analysis. This study explores the application of Micellar Electro Kinetic Chromatography (MEKC) and High-Performance Liquid Chromatography (HPLC) for this purpose. In MEKC method, the separation was done using fused silica capillary (41.5 cm × 50 µm id) and a back ground electrolyte consisting of 50 mM borate buffer (pH 9) containing 50 mM sodium lauryl sulphate (SLS) and 10% organic modifier (Acetonitrile). In HPLC method, separation was performed on a ZORBAX Extend-C18 (4.6 × 250 mm, 5 µm) column, using a gradient mobile phase consisting of 50 mM phosphate buffer pH 3 and methanol. Both methods attained good linearity (r ≥ 0.9996) with low values of LOD and LOQ. Both methods were successfully applied in the determination of co-administered single, binary and ternary dosage form of the studied drugs. Moreover, application of various combinations of co-administered dosage forms was achieved in rat plasma, confirming the applicability of these methods in different matrices. The use of micellar solutions in MEKC enhances separation efficiency while reducing the need for organic solvents, aligning with green chemistry principles. HPLC methods were optimized using environmentally benign solvents, ensuring reduced toxicity and waste production. The methodologies were evaluated through green, white, and blue metrics to ensure comprehensive sustainability, considering ecological impact, safety, and practical efficiency. These methods were not only cost-effective and time-saving but achieved high efficiency, sensitivity, and reproducibility making them ideal for routine use in pharmaceutical analysis. [ABSTRACT FROM AUTHOR]

A systematic investigation of the photoinduced [6π]‐electrocyclization reaction of diphenylamine and N‐methyldiphenylamine has been carried out under steady‐state and time‐resolved conditions in homogeneous (cyclohexane, acetonitrile and methanol) and micellar solutions (sodium dodecyl sulfate ‐SDS, cetyltrimethylammonium chloride‐CTAC and polyethylene glycol monododecyl ether‐Brij P35). The photolysis of such compounds in both homogeneous and micro‐heterogeneous media afforded the corresponding carbazoles in almost quantitative yield under oxidative conditions. Furthermore, the relative rate of formation of the photoproducts increases when moving from homogeneous media to micellar solution, due to the environmental confined and hydrophobic micellar core as highlighted by 1D and 2D NMR (NOESY and DOSY) spectroscopic analyses. [ABSTRACT FROM AUTHOR]

This study presents the self-assembly of polyethylene oxide (PEO)-block-polypropylene oxide (PPO)-block-polyethylene oxide (PEO)-based block copolymer (BCP) commercially known as Pluronic® P123 in water and in the presence of different copolymeric surfactants (L61, L62, L64, and F68) with varying degree of hydrophilicity, i.e., %EO content. The clouding behavior demonstrates the varied phase transition ranging from solution, blue point (BP), and cloud point (CP). The characteristics of the micelles in the single and mix system are characterized utilizing dynamic light scattering (DLS) and small-angle neutron scattering (SANS) techniques at different temperatures. These scattering approaches provide an insightful information on the micelle size and shape. The size variations in self-assembled micelles designated the micelles to undergo growth/transition in shape from spherical to elongated ellipsoidal as function of temperature. Additionally, the application of these nanoscale micellar aggregates as carriers for delivering the anticancer drug Quercetin (QCT) was undertaken by a thorough quantitative and qualitative analysis to gain valuable insights into the effectiveness of the mix-micellar system as an ideal platform for drug delivery. A comprehensive investigation of drug release kinetics is presented using various kinetic models. The MTT (cytotoxicity assay) assay is used to gauge the effectiveness of the QCT-loaded copolymeric micelles. Micellar transition of 5% w/v P123 in water and in the presence of copolymeric surfactants as additives at 0.2% weight fraction (fix) at different temperatures [ABSTRACT FROM AUTHOR]

The current research is focused on the discovery and optimization of an effective cosmetic carrier of alpha-bisabolol as a first step in the development of a cosmetic product with cleansing and antimicrobial action for facial skin hygiene. A micellar solution of Poloxamer 407 was selected as a cosmetic base because of the good washing ability, easy application, and high tolerability of this polymeric surfactant. The solubilization capacity of a 5% micellar solution with respect to α-bisabolol was investigated by applying varying solubilization techniques and increasing concentrations of the oily active substance. The test samples were subjected to an accelerated physical stability test, viscosimetry, dynamic light scattering (DLS), electrophoretic light scattering (ELS), foamability test, and antimicrobial screening. Over the course of this research, the advantage of the film-hydration method over direct solubilization was demonstrated by the narrower size distribution and smaller hydrodynamic size of the micellar nano-carriers (ranging from 29.02 to 116.5 nm) and the respective higher physical stability of the dispersions. The optimized composition was found to be suitable for application on large skin areas in terms of viscosity in the temperature range from 20 °C to 40 °C (3.4–2.3 mPa.s). Preservation of the washing capacity of the micellar solution in the presence of solubilized α-bisabolol was established. The active composition demonstrated inhibitory activity against Staphylococcus aureus and Escherichia coli and fungicidal activity against Candida albicans. This study concludes that the optimal concentration of α-bisabolol to be solubilized in a 5% Poloxamer 407 micellar solution by the film-hydration technique is 1%, considering the desirable physical endurance and antimicrobial activity. [ABSTRACT FROM AUTHOR]

Hypothesis: The physical and mechanical properties of triacylglycerols (TAGs), or 'fats', depend on their composition and thermal history which, in turn, impact crystal structure and morphology. We examine whether thermal history can be mechanistically related to film removal by a surfactant solution. Experiments: Model TAG mixtures, comprising triolein:tripalmitin:tristearin 0.5:0.3:0.2, were subjected to a range of cooling profiles from the melt (0.5-80 °C/min, Newtonian and annealed), and the resulting solid films characterised by microscopy, X-ray diffraction, infrared spectroscopy, and contact angle measurements. Film removal from a model glass substrate by an aqueous surfactant solution of sodium dodecylsulphate and dodecyldimethylamine oxide at room temperature fixed at 25 °C was examined under quiescent flow conditions. Findings: Quantitative relations are established between TAG cooling profile, crystal structure and morphology, surface energy γ S F E , and removal (or 'cleaning'). In general, films cooled slowly from the melt yield heterogeneous morphologies with predominantly β 1 ′ phase, higher polar γ S F E , and faster removal timescales. By contrast, rapid cooling results in homogeneous films, rich in β 2 ′ phase, low polar γ S F E , and long removal times. Our results elucidate the non-trivial impact of TAG thermal history, connecting the multiscale semi-crystalline structure to surface energy, and eventually to film delamination by micellar solutions. [ABSTRACT FROM AUTHOR]

We present the synthesis of a novel benzimidazolium-based surface active ionic liquid (SAIL), 3-dodecyl-1H-3λ-benzo[d]imidazole chloride, a SAIL with excellent surface activity and self-aggregation tendency whose aqueous micellar solutions offer exceptional solubilizing capacity and electrocatalytic performance for efficient electrocarboxylation of halocarbons. [ABSTRACT FROM AUTHOR]

Bio‐inspired by natural species and previous research works, nanotubes are prepared by soft‐template electropolymerization in micellar solution. Various thiophene‐based and carbazole‐based monomers are designed from a triphenylamine core. With one of the carbazole‐based monomers, which is fully conjugated and with a star‐like structure, gecko‐like surface structures are obtained even if the structure is not perfectly planar. Extremely long and densely packed‐microtubes are reached especially at constant potential. However, the surfaces are not both highly hydrophobic and with strong water adhesion, but are superhydrophilic. These wetting properties can be explained by a high surface energy (γSV)=41.9 mN m−1 compared to gecko foot even if the natural gecko feet are also chemically inhomogeneous, or by differences in the arrangement of the surface structures. [ABSTRACT FROM AUTHOR]

We present a dissipative particle dynamics study of surfactant solutions under shear, which allows us to investigate their rheological properties. We consider a variety of concentrations and phase structures, including micellar solutions and liquid crystal phases. It is shown that the viscosity of micellar solutions increases as a function of concentration, in agreement with what is expected from experimental data. We also show that micelles can exhibit shear-thinning behavior when a shear force is applied, which is a result of micelles breaking down into smaller aggregates. Lamellar and hexagonal phases are found to orientate under the application of shear, in agreement with experimental observations. It is normally suggested that lamellar phases under shear can exhibit a transition between orientations as the shear rate is increased, usually as a result of lower viscosity. We calculate the viscosity for different lamellar phase orientations, showing that, although the viscosity of perpendicular orientations is lower than that of parallel orientations, we do not observe a transition to the perpendicular phase at high shear rates. Finally, we show that the choice of Schmidt number has a significant impact on the results, which is important for determining the correct behavior via simulations. [ABSTRACT FROM AUTHOR]

[Display omitted] Hypothesis: Lipid nanoparticle self-assembly is a complex process that relies on ion pairing between nucleic acids and hydrophobic cationic lipid counterions for encapsulation. The chemical factors influencing this process, such as formulation composition, have been the focus of recent research. However, the physical factors, particularly the mixing protocol, which directly modulates these chemical factors, have yet to be mechanistically examined using a reproducible mixing platform comparable to the industry standard. We here utilize Flash NanoPrecipitation (FNP), a scalable rapid mixing platform, to isolate and systematically investigate how mixing factors influence this complexation step, first by using a model polyelectrolyte-surfactant system and then generalizing to a typical RNA lipid nanoparticle formulation. Experiments: Aqueous polystyrene sulfonate (PSS) and cetrimonium bromide (CTAB) solutions are rapidly homogenized using reproducible FNP mixing and controlled flow rates at different stoichiometric ratios and total solids concentrations to form polyelectrolyte-surfactant complexes (PESCs). Then, key mixing factors such as total flow rate, inlet stream relative volumetric flow rate, and magnitude of flow fluctuation are studied using both this PESC system and an RNA lipid nanoparticle formulation. Findings: Fluctuations in flow as low as ± 5 % of the total flow rate are found to severely compromise PESC formation. This result is replicated in the RNA lipid nanoparticle system, which exhibited significant differences in size (132.7 nm vs. 75.6 nm) and RNA encapsulation efficiency (34.0 % vs. 82.8 %) under fluctuating vs. steady flow. We explain these results in light of the chemical variables isolated and studied; slow or nonuniform mixing generates localized concentration gradients that disrupt the balance between the hydrophobic and electrostatic forces that drive complex formation. These experiments contribute to our understanding of the complexation stage of lipid nanoparticle formation and provide practical insights into the importance of developing controlled mixing protocols in industry. [ABSTRACT FROM AUTHOR]

Coarse grained simulations were adopted to describe the encapsulation and dispersion of fullerene C$_{60}$ 60 by hexaoxyethylene dodecyl ether (C$_{12}$ 12E$_6$ 6) surfactants. The self-organised structures of C$_{12}$ 12E$_6$ 6 molecules in water were captured and the characteristics of micelles composed of different number of C$_{12}$ 12E$_6$ 6 molecules were analysed. We found that C$_{60}$ 60 molecules alone or in clusters can spontaneously translate into the hydrophobic core of micelles. One monomeric C$_{60}$ 60 can explore the hydrocarbon-chain region of the micelles with different sizes, and two different preferential locations of C$_{60}$ 60 are observed. The small C$_{60}$ 60 clusters can disaggregate after entering the micelle. Larger C$_{60}$ 60 clusters can penetrate into the micelle as solid-like nanoparticles, although they are partially disaggregated. When investigating the self-assembly of C$_{12}$ 12E$_6$ 6 surfactants and C$_{60}$ 60 molecules, we found that it is very difficult to disperse C$_{60}$ 60 in the micelle monomolecularly. At high molar ratio of C$_{12}$ 12E$_6$ 6/C$_{60}$ 60, colloidal nanoC$_{60}$ 60 aggregates form with C$_{12}$ 12E$_6$ 6 surfactants adsorbed on the surface. Our simulations provide an explanation for the different observations in fullerene solubilization in micellar solutions and give a guideline for further solubilization of pristine fullerene or small hydrophobic molecules with surfacant micelles, which is helpful for the design of new micelle-based delivery vehicles. [ABSTRACT FROM AUTHOR]

The reported work is focused on the solubility of Rhodamine B (cationic dye), as an important methodology to investigate the extent of incorporation or penetration of dye inside the micelles spectroscopically, so the solubilised dye can be filtered via Micellar-enhanced ultrafiltration process to keep our environment safe from toxic effects of industrial effluent. Solutions were prepared by using micellar media of anionic surfactants i.e. Sodium dodecyl sulphate (SDS), Sodium Oleate (SO) as well as mixed micellar media of said anionics with non-ionic surfactant i.e. Triton X-100 (TX-100). The extent of solubilisation has been, quantitatively, calculated using data of differential spectroscopy, in terms of partition coefficient Kx and Gibbs energy of partition, ∆Gp. It has been observed that mixed micellar media has better solubilisation capacity than micellar solution of individual surfactants. A better micellar solubilisation and ultimately the high Gibbs energy of partition, ∆Gp with SO/TX-100 system i.e. −40.89 as compared to SDS/TX-100 system (−37.03) has been observed due to the presence of long carbon chain in SO. [ABSTRACT FROM AUTHOR]

Preparing well-ordered nanotubes on material surface is fundamental for a huge number of applications. Natural surfaces and theoretical approaches show that porous structures such as nanotubes are key parameters for both surface hydrophobicity and water adhesion. Here, a very easy soft-template electropolymerization approach is used to form nanotubes. A solvent of low water-solubility (dichloromethane) is mixed to water in the presence of a surfactant electrolyte for stabilizing the micelles formed in solution. The monomers investigated are thiophene and carbazole derivatives, and are all fully conjugated for favoring the deposition versus polymerization. Indeed, in all the electrodeposited films, the monomer is mostly present as confirmed by cyclic voltammetry. The key parameters in the resulting nanotubes is the monomer structure because a preferential growth is necessary and this one is induced here especially by π-stacking interactions in the direction perpendicular to monomer. The surfaces composed of nanoparticles or nanotubes are the most hydrophobic with an apparent contact angle up to 130.9° accompanied with strong water adhesion, as reported on gecko foot or rose petal. [ABSTRACT FROM AUTHOR]

In this study, a new bioamphiphile sodium-2-decanamyde-2-methyl propanoate (SDMP) was synthesized to study the photophysical properties of bromelain (BM) in its micellar medium, and the experiment was further extended with the addition of room-temperature ionic liquids (RTILs) and a commonly used anionic surfactant sodium dodecyl sulfate (SDS), salt sodium chloride (NaCl) and a cationic drug nortriptyline (NOT) using steady-state and time-resolved spectroscopy, along with other techniques. For the modulation of the photophysical properties of BM, the interaction of BM was first studied with an SDMP micelle and then with two ILs of different chain lengths, SDS and NOT. This study reveals that micellar assemblies significantly reduce the degradation rate of bromelain owing to partitioning in the palisade layer of micelles from bulk water. The increase in average lifetime with the addition of SDMP after the micellar zone may be the result of hindrance of the excited-state intramolecular proton transfer (ESIPT) process. Furthermore, the stability and activity were compared with those of conventional imidazolium-based ionic liquids, i.e., 1-hexadecyl-3-methylimidazolium chloride (C16MeImCl) and 1-decyl-3-methylimidazolium chloride (C10MeImCl), using spectroscopic techniques. The present study shows that both the studied ILs interact with the functional groups of BM. Therefore, it appears that the SDMP micellar medium stabilizes BM more than an aqueous medium. The interaction between BM and amino acid surfactant (AAS) may provide new insights in the field of green technology using renewable natural resources to create eco-friendly and bio-degradable products. [ABSTRACT FROM AUTHOR]

The properties of natural polyphenol curcumin in water solutions of cationic Gemini surfactants decamethoxin and ethonium, which have similar positively charged nitrogen hydrophilic head groups but different spacer sizes and lengths of hydrophobic tails have been investigated in a wide range of concentrations by using UV–Vis spectroscopy and quantum‐chemical calculations. It was found that curcumin dissolves in the organized micellar media of these surfactants in the enol tautomeric form and its solubility increases 400 times compared to water. The binding constants of curcumin with decamethoxin and ethonium were determined by the solubility method. Significant differences in the influence of premicellar concentrations of cationic Gemini surfactants on the solubility and tautomeric transformations of curcumin were revealed. In contrast to decamethoxin, ethonium at a concentration below the CMC promotes a significant increase in the solubility of curcumin and a shift in the tautomeric equilibrium towards the formation of its keto form. [ABSTRACT FROM AUTHOR]

The micellization properties of mixed aqueous solutions of a cationic gemini surfactant (CGS) and Triton X‐100, a conventional non‐ionic surfactant, with various mole fractions, were determined by measuring the surface tension at different temperatures. Various theoretical models were used to analyze the behavior of this mixed system. The interactions between CGS and Triton X‐100 were determined to be non‐ideal and synergistic. The calculated interaction parameters (βM) have negative values at all temperatures and for all mole fractions, showing attractive interactions. It was found that increasing the mole fraction of Triton X‐100 significantly increased the synergistic effect (more negative values). Micellar aggregation number (Nagg) values of pure surfactants and their mixtures in different ratios were obtained with the steady‐state fluorescence quenching method. Furthermore, the molar solubilization ratio of Sudan III organic dye in all surfactants aqueous systems was obtained using UV–Visible spectrophotometry. At concentrations above critical micelle concentration, the solubility of Sudan III in water was substantially increased linearly for all systems and it was observed that the enhancement was even more significant for mixed surfactant systems. [ABSTRACT FROM AUTHOR]

In the current study, a tetracationic quaternary ammonium salt (TCQAC) was synthesized and characterized and its ability to suppress corrosion on mild steel (MS) in a 0.5 M H2SO4 solution was examined. Various chemical, electrochemical, and surface characterization techniques were utilized to study the inhibition efficiency of TCQAC. The TCQAC manifests 99.83% efficiency at 20 ppm concentration. Out of all the examined isotherm models, the Langmuir isotherm offered the best fit for the TCQAC adsorption on the MS surface. A very high negative value of ΔGads (−45.18 kJ mol−1) suggests that the adsorption of TCQAC followed the chemisorption mechanism. Electrochemical studies indicate that TCQAC increases the linear and charge transfer resistances (LPR and Rct, respectively). TCQAC slows down the anodic and cathodic Tafel reactions; however, it acts as an anodic‐type inhibitor at 5, 10, and 20 ppm. The appearance of extra Cl and N signals in the energy dispersive x‐ray (EDX) spectrum and an improvement in surface smoothness in the scanning electron microscope (SEM) image of the inhibited sample corroborated the adsorption method of corrosion inhibition. X‐ray photoelectron spectroscopy (XPS) study indicates that TCQAC creates corrosion preventive layers by chemical adsorption. In Frontier molecular orbitals (FMOs), highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were delocalized around the central part that comprises two benzyls, four allyls, and one hydrocarbon ((CH2)6) moieties and two quaternary nitrogen atoms. The outcomes of XPS and density functional theory (DFT) analyses indicate that the chemisorption of TCQAC occurs by dπ–pπ bonding with the surface iron atoms. The π‐electrons of aryl and allyl moieties extensively participate in the bonding. [ABSTRACT FROM AUTHOR]

The network formed by wax precipitation at low temperature and colloid asphaltene at high temperature leads to poor fluidity of heavy oil, and the gelling characteristics of crude oil lead to pipeline blockage, which affects the exploitation, transportation and refining of crude oil. This work prepares a series of cationic surfactant-modified nano hydrotalcite (CSNH) to weaken the network structure and enhance the fluidity of the crude oil by the interaction of organic and inorganic functional groups on the CSNH surface and the components of the crude oil. The results show that CSNHs can all reduce the viscosity of crude oil from different oilfields, among which BTNH can reduce the viscosity of Yanglou (YL) crude oil by 98.8% (31 °C) and depress the pour point by 16.0 °C at most. In the investigation of the universality of crude oil, the modified hydrotalcite was applied to the mixed crude oil (CQH) of Changqing Oilfield, the crude oil (J76) of Jidong Oilfield, the high pour point oil (GN) of Huabei Oilfield, and the crude oil (HQ) of Tuha Oilfield. The viscosity reduction rates were 53.2%, 86.2%, 42.7%, and 63.8%, respectively. The characterization of this nano material confirms the modification of quaternary ammonium cationic surfactant on the surface, resulting in a smaller particle size, and the nano particles are stable under conventional conditions. The mechanism of viscosity and pour point reduction in crude oil by BTNH was discussed by DSC and optical microscopy analysis. The OH- and long-chain alkyl groups on the BTNH surface may interact with the resins, asphaltene and wax through hydrogen bonding and co-crystal, weakening or dispersing their aggregates, thereby improving the fluidity of crude oil. Finally, a cost evaluation was conducted on BTNH, providing useful support for subsequent promotion and application. [ABSTRACT FROM AUTHOR]

Hydrotropes are amphiphiles that improve the water solubility of hydrophobic substances. In this study, we systematically evaluated the effects of eight hydrotropes on the antibacterial activity of fatty acids solubilized in a micellar system. The antibacterial activity was evaluated using minimum inhibitory concentration (MIC) as an indicator, and CMC was calculated for interfacial properties based on the measurement of the surface tension and the solubilization behavior of the oil‐soluble dye. The solubilization of lauric acid (12:0 FA) in the micelles of nonionic surfactants increased and decreased the antibacterial activities of the surfactants against Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis, respectively. The addition of the hydrotropes decreased the antibacterial activity of the surfactants against both Staphylococci. However, on introducing small amounts of 12:0 FA, the surfactants exhibited selective antibacterial activity against S. aureus. These antibacterial phenomena were observed at concentrations above the critical micelle concentration of the surfactants. These findings suggest that the addition of hydrotropes affects the interfacial properties and antibacterial activity of micellar systems containing antibacterial ingredients. [ABSTRACT FROM AUTHOR]

The stereoselective synthesis of biobased nonionic sugar surfactants (polyhydroxy surfactants), which are thought to be safer, more affordable, plentiful, biodegradable, biocompatible, and possess mildness and performance in formulation, is becoming increasingly popular as people become more aware of the potential negative effects of conventional surfactants on the environment and human health. Reviewing the stereoselective synthesis of polyhydroxy surfactants is the objective of this article. Additionally, it emphasizes the synthesis and application of sugar‐based surfactants in everyday life, as well as their description and the influence of outside factors. A thorough assessment of the literature on biobased polyhydroxy surfactants including alkyl polyglycosides, sorbitol esters, sucrose esters, fatty acid glucamides, and methyl glucosides was studied for methodology. The characterization of the surfactants shows an exponential increase in electrical conductivity when there is an increase in the water volume fraction. The surface tension also showed a linear relationship with surfactant concentration, such that as the concentration increases, the surface tension of the solution decreases. The effect of external parameters on polyhydroxy surfactants was also studied, which shows that increasing temperature favors micellization initiation at a lower concentration. Likewise, the micellar molecular weight and the hydration per unit mass of the surfactants decrease with an increase in the pH value. Evidence to further support these biobased surfactants as substitutes for their petrochemical counterparts is advantageous as worldwide legislation and user requirements for sustainability and safety expand. [ABSTRACT FROM AUTHOR]

The reduction kinetics of N,N′-phenylenebis(salicylideneiminato)iron(III), [Fe(salphen)]+ by thioglycolic acid (TSH) has been carried out in mixed aqueous medium (DMSO:H2O; 1:4) in pseudo-first order condition at 26 ± 1 °C. A CORNING colorimeter 253 was used to monitor the reaction rates by detecting the absorbance reduction of the reaction at 435 nm. The reaction was acid independent, second order overall and demonstrated zero Brønsted-Debye salt effect. Ions such as Mg2+ and CH3COO- catalyzed the reaction. The thermodynamic parameters indicated an activated complex that is much ordered and a highly solvated transition state. Reaction catalysis was observed in the case of sodium dodecylsulphate (SDS) and cetyltrimethylammonium bromide (CTAB) inclusion. The critical micelle concentrations obtained for SDS were 8.0 × 10−3 and 3.3 × 10−3 mol dm−3 whereas that observed for CTAB were 2.0 × 10−3 and 2.8 × 10−3 mol dm−3 in water and [Fe(salphen)]+ reaction media respectively. Piszkiewicz model was used to analyze the results which indicated the existence of pre-micellar aggregates and significant electrostatic and hydrophobic interactions between the metal complex and the pre-micellar aggregates of the surfactants. The cooperativity index and binding constants obtained were n = 1.22, K = 4.78 × 104 dm3 mol−1, n = 1.27 and K = 4.55 × 104 dm3 mol−1 respectively for SDS and CTAB. A plausible mechanism suggesting an outer-sphere mechanism has been postulated. [ABSTRACT FROM AUTHOR]

The adoption of green chemistry principles has ushered in significant advancements in environmental safety and cost efficiency across various synthetic processes. One notable area of improvement lies in reducing the hazardous waste generated by using organic solvents in organic reactions. In contrast, the utilization of water as a solvent has emerged as a sustainable and environmentally friendly alternative. Micellar catalysis, driven by tailor-made surfactants, has played a pivotal role in enhancing water’s efficacy as a solvent in organic synthesis. These designer surfactants boast unique structures that enhance the solubility of organic compounds in water and act as initiators or stabilizers for nanoparticle catalysts, facilitating efficient catalysis. Micelles function as nanoreactors, creating localized high concentrations of reactants that lead to unprecedented reaction rates and exceptional selectivity. This review underscores the plethora of sustainable protocols that have yielded outstanding results by leveraging aqueous micellar chemistry in pharmaceutical synthesis. Moreover, the review explores the integration of nanocatalysis using readily available first-row transition metals, with a particular emphasis on the role of surfactants in stabilizing the catalyst. The versatility of the proline-based surfactant PS-750-M as a ligand or capping agent, enabling ligand-free metal nanocatalysis, is also addressed. Lastly, the review addresses current challenges and future avenues in green chemistry, stressing the importance of ongoing research and innovation. [ABSTRACT FROM AUTHOR]

Enzymatic synthesis of enantiopure chiral halogenated aryl alcohols by ketoreductases (KREDs) is emerging but still challenging, due to the low solubility and slow mass transfer in aqueous media. As an ecofriendly tool for this issue, amphiphilic micelles are attractive. Herein, KRED-catalyzed reduction of halogenated aryl ketones in a TPGS-750-M formed aqueous micellar solution was conducted, achieving the corresponding chiral alcohols with moderate to excellent yields of up to 99% and remarkable enantioselectivities of >99% ee under the optimal conditions. Notably, the performance strengthening mechanisms of micelles in this process are illustrated, in which the solubilization position of the substrate plays an essential role and the substrates solubilized in the palisade layer of the micelles exhibit the highest increases in conversion and enantioselectivity. These findings provide guidance for rational design of enzyme catalysis in aqueous micellar media. [ABSTRACT FROM AUTHOR]

The 5CB liquid crystal droplets were found to self-propel when suspended in a micellar solution of surfactant. We report experimental studies on the motion of these droplets in a quasi-two-dimensional geometry. The droplets exhibit directed, self-avoiding, or random coiling trajectories depending on the size of the droplets compared to the height of the sample cell. The flattened droplets showed smoother trajectories and with self-crossing. Interestingly, the large flattened droplets were found to exhibit deformation of their apparent cross-section during their self-propulsive motion. These unique properties of self-propulsion of 5CB liquid crystal droplets in surfactant solution can provide a new opportunity to study active biomimetic systems. [ABSTRACT FROM AUTHOR]

Droplet Interface Bilayers (DIBs) constitute a commonly used model of artificial membranes for synthetic biology research applications. However, their practical use is often limited by their requirement to be surrounded by oil. Here we demonstrate in-situ bilayer manipulation of submillimeter, hydrogel-encapsulated droplet interface bilayers (eDIBs). Monolithic, Cyclic Olefin Copolymer/Nylon 3D-printed microfluidic devices facilitated the eDIB formation through high-order emulsification. By exposing the eDIB capsules to varying lysophosphatidylcholine (LPC) concentrations, we investigated the interaction of lysolipids with three-dimensional DIB networks. Micellar LPC concentrations triggered the bursting of encapsulated droplet networks, while at lower concentrations the droplet network endured structural changes, precisely affecting the membrane dimensions. This chemically-mediated manipulation of enclosed, 3D-orchestrated membrane mimics, facilitates the exploration of readily accessible compartmentalized artificial cellular machinery. Collectively, the droplet-based construct can pose as a chemically responsive soft material for studying membrane mechanics, and drug delivery, by controlling the cargo release from artificial cell chassis. Droplet interface bilayers can be used as a model of artificial membranes for synthetic biology and drug delivery applications, however, their accessibility using non-invasive techniques remains challenging. Here, the authors develop an in-situ bilayer manipulation of encapsulated droplet interface bilayers in hydrogel capsules, generated by high-order emulsification in monolithic 3D-printed microfluidic devices. [ABSTRACT FROM AUTHOR]

Context: This study involves simulating the process of inhibiting corrosion through the formation of micelles by surfactants and their deposition on iron (Fe) surfaces. The primary focus is on examining CTAB/SDS mixtures in aqueous solutions with different concentrations. Micelle properties, including size, shape, aggregation number, cluster size, and surfactant diffusion, were calculated and validated with experimental data. The coarse-grained Fe surface was modeled and validated against experimental water contact-angle data. Subsequently, the deposition of CTAB/SDS mixtures on the Fe surface and air–water interface was studied systematically. We found that the relative ratio of CTAB/SDS in the solution directly influences surfactant deposition behavior, which might impact the corrosion inhibition efficiency. Methods: All the MD simulations were performed using the GROMACS software with MARTINI2 force field and Martini polar water. The molecules are packed using PACKMOL software. Both NVT and NPT simulations are caried out at temperature and pressure of 303 K and 1 bar respectively, with a nonbonded interaction cut-off (rcut) of 1.1 nm. The LJ potential was shifted from 0.9 nm to rcut, while the electrostatic potential was shifted from 0.0 nm to rcut. For electrostatics, reaction-field coulomb type is used, relative dielectric constant (epsilon-r) and the reaction field dielectric constant (epsilon-rf) are equal to 2.5 and infinity respectively. The dielectric constant below rcut is epsilon-r, and beyond the cut-off is epsilon-rf. Coulomb-modifier used as potential-shift which leads to shift in the coulomb potential by a constant such that it is zero at the rcut. This makes the potential of the integral of the force. The neighbor list was updated every 10 steps, employing a neighbor list cut-off equal to rcut. Using a polar water model, we used a constant time step of 0.02 ps throughout the simulation. The used epsilon-r = 2.5, is recommended for polar water. [ABSTRACT FROM AUTHOR]

Research and development of novel fluorine‐free materials to replace fluorinated aqueous film‐forming foam (AFFF) are crucial for improving pool fire suppression performance and protecting the environment. In this study, we report the thermo‐responsive fluorine‐free foam stabilized by triblock PEO–PPO–PEO copolymers (EO)100(PO)65(EO)100 for pool fire suppression. Small‐angle X‐ray scattering (SAXS) and reflected light interferometric techniques are conducted to study the molecular self‐assembly in bulk and film thinning behavior, and the foaming kinetics of copolymer solution and thermophysical properties of the liquid foam are studied by dynamic surface tension and oscillatory rheology analysis. At room temperature, the amphipathic structure of PEO–PPO–PEO makes it possible to absorb at the air–liquid interface forming large‐scale liquid foams containing the mobile films with a detergent state. Upon heating to the surface cooling temperature of burning oil, the mobile films can be actively switched into mechanically strong films with rigid surfaces. The in situ switching of the two interfacial states leads to the significant enhancement of the foam stability, especially under the dual defoaming effects of heat and oil. What's more, it is observed that the confinement of organized copolymer micelles in the Plateau borders and micellar self‐layering in film confinement induce drainage delay of foam and film's stepwise thinning phenomenon, further increasing film thickness and enhancing the thermal stability of the foam. In standard fire‐fighting tests, it is proved that the burnback performance exhibited by thermo‐responsive copolymer foams is three times better than that for classical fluorine‐free foams and almost 1.5 times higher than that for commercial AFFF. [ABSTRACT FROM AUTHOR]

Ultrafiltration membranes in the fields of water treatment and biomedicine should have high permeability as well as antibacterial and antifouling capabilities. In this study, a novel, controllable, self-assembled soft micelle particle based on the combination of tri-block-copolymers and dopamine hydrochloride is designed as a multifunctional additive. High molecular weight polyvinylpyrrolidone k85 was used as a pore forming and hydrophilic agent. Liquid–liquid phase transformation was used to modify a polyether sulfone-based membrane. The morphology and characteristics of the modified membranes were analyzed via X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, laser confocal microscopy, water contact angle, permeability measurements, mechanical measurements, and antifouling and antibacterial tests. Moreover, the zwitterionic blend polyether sulfone ultrafiltration membrane possessed an overall electrically neutral segment, resulting in a high water flux, water flux recovery rate, and BSA retention rate. The pure water flux of the modified membrane was as high as 422 L m−2 h−1, and the rejection rate of bovine serum albumin was 97.83%. Additionally, the modified membrane demonstrates an effective antibacterial performance against Escherichia coli. [ABSTRACT FROM AUTHOR]

Two new copper(II) complexes (1 and 2) with reduced L -histidine Schiff bases were synthesized and characterized using single-crystal X-ray diffraction, powder X-ray diffraction, UV-visible spectroscopy, and thermal analysis. Single-crystal analysis reveals that 5-methyl-containing 1 possesses a simple phenoxo-bridged binuclear unit, while 5-bromine-substituted 2 possesses a metal–organic cage (MOC) structure. The as-prepared complexes as artificial metallohydrolases displayed catalytic activity towards the hydrolysis of both PNPP (p-nitrophenyl picolinate) and PNPA (p-nitrophenyl acetate). These two complexes provided 28-fold (for 1) and 39-fold (for 2) rate enhancements in comparison with spontaneous hydrolysis of PNPA, respectively. With regard to PNPP, its hydrolysis was accelerated by two orders of magnitude in the presence of 1 or 2. Additionally, positive micellar effects of bis(hexadecyldimethylammonium)hexane bromide (16-6-16) and N-octyldocosylammonium bromide (C22H45N(CH3)2C8H17Br, abbr. C22/8) were observed for the PNPA hydrolysis by 1 or 2, resulting in 1.3 to 3.9 times acceleration compared to that in buffered aqueous solution. In micellar solution of N,N-dimethyl-n-lauroylsarcosine sodium (LSS), no obvious rate enhancement was observed for the PNPA hydrolysis by 1 or 2. [ABSTRACT FROM AUTHOR]

We introduce an innovative theoretical framework tailored for the analysis of Pair Distribution Function (PDF) data derived from Small-Angle X-ray Scattering (SAXS) measurements of core-shell micelles. The new approach involves the exploitation of the first derivative of the PDF and the derivation of analytical equations to solve the core-shell micelle structure under the hypothesis of a spheroidal shape. These analytical equations enable us to determine the micelle's aggregation number, degree of ellipticity, and contrast in electron density between the core-shell and shell-buffer regions after having determined the whole micelle size and its shell size from the analysis of the first derivative of the PDF. We have formulated an overdetermined system of analytical equations based on the unknowns that characterize the micelle structure. This allows us to establish a Figure of Merit, which is utilized to identify the most reliable solution within the system of equations. [ABSTRACT FROM AUTHOR]

There is a consensus that we are conscious of something greater than ourselves, as if we are derived from some other primordial set of principles. Classical or Newtonian physics is based on the Laws of Nature. Conversely, in a recent series of articles, it has been hypothesized that the cell was formed from lipid molecules submerged in the primordial ocean that covered the earth 100 million years after it formed. Since lipids are amphiphiles, with both a positively- and negatively-charged pole, the negatively-charged pole is miscible in water. Under the influence of earth's gravity, the lipid molecules stand up perpendicularly to the surface of the water, packing together until the negative charge neutralizes the Van der Waals force for surface tension, causing the lipid molecules to 'leap' into the micellar form as a sphere with a semi-permeable membrane. Particles in the water freely enter and exit such spheres based on mass action. Over time such protocells evolved Symbiogenesis, encountering factors that posed existential threats, assimilating them to form physiology to maintain homeostatic control. Importantly, when differentiated lung or bone cells are exposed to zero gravity, they lose their phenotypic identity in their evolved state, which has been interpreted as transiting from local to non-local consciousness. [ABSTRACT FROM AUTHOR]

Photosensitive micellar solutions of mixed surfactants and photosensitive additives have gained much interest. However, there are no reports on photosensitive micellar solutions containing trimeric cationic surfactant. In the study, novel photosensitive viscoelastic micellar solutions consisting of trimeric cationic surfactant (TEC) and trans‐ortho‐methoxycinnamic acid (trans‐OMCA) were investigated. This study utilized rheology, UV–vis spectroscopy, and cryo‐TEM to investigate the photo‐responsive behavior and mechanism of the TEC/trans‐OMCA micellar solutions. Rheological studies revealed that the concentration of TEC and trans‐OMCA, as well as temperature, significantly affected the viscoelastic properties of the micellar solutions. Furthermore, the Carreau and Maxwell models might be used to characterize the flow curves and viscoelasticity of the micellar solutions, respectively. Notably, TEC/trans‐OMCA micellar solutions exhibited excellent light‐induced thinning characteristic, with the optimal performance at a mass ratio of φ = 0.5. After UV irradiation, the zero‐shear viscosity of TEC/trans‐OMCA (0.6/0.3 wt%) micellar solution was reduced by 352 times, while the viscoelasticity and the area of hysteresis loops were significantly reduced. This drastic change in the rheological characteristics of the micellar solutions could be attributed to the photoisomerization of trans‐OMCA and the resulting changes in the internal microstructure of the solutions. Moreover, the viscosity of the micellar solutions diminished as the temperature increased, with the remaining viscosity of the TEC/trans‐OMCA (1.0/0.5 wt%) micellar solution at 36.4 mPa s at 95°C. This study expands on the potential utilization of oligomeric surfactants in the construction of photorheological viscoelastic fluids. [ABSTRACT FROM AUTHOR]

[Display omitted] The question of why aqueous solutions of some surfactants demonstrate a rapid spreading (superspreading) over hydrophobic solid substrates, while solutions of other similar surfactants do not, has no definitive explanation despite numerous previous studies. The suggested hypothesis for this study assumes that once the spreading coefficient of surfactant is positive, there is a concentration range for solutions of any surfactant which demonstrates rapid spreading. As it is impossible to calculate spreading coefficients for solid substrates, we compare the spreading performance of known superspreaders and non-superspreaders on liquid (oil) substrate. The kinetics of spreading of aqueous solutions of a series of branched ionic surfactants and non-ionic trisiloxane surfactants on two liquid substrates was studied and compared with the spreading of a surfactant-free liquid, silicone oil. Both dynamic and equilibrium spreading coefficients were calculated using measured surface and interfacial tensions. There is no difference in spreading rate on liquid substrate between solutions of surfactants proven as superspreaders (while spreading on solid substrate) or non-superspreaders. A rapid spreading (superspreading) with the characteristic rate of spreading O(102–103) mm2/s occurs if the dynamic spreading coefficients exceeds the positive threshold value. If the dynamic spreading coefficient is negative or slightly positive, complete wetting still occurs, but the spreading is slow with the spreading rate is O(1) mm2/s. Spreading exponents for surfactant solutions in the rapid spreading regime are considerably larger than for the surfactant-free liquid. A number of spreading and dewetting patterns were observed depending on the surfactant type, its concentration and substrate. [ABSTRACT FROM AUTHOR]

Efficient intratumoral penetration is essential for nanomedicine to eradicate pancreatic tumors. Although nanomedicine can enter the perivascular space of pancreatic tumors, their access to distal tumor cells, aloof from the vessels, remains a formidable challenge. Here, we synthesized an acid-activatable macromolecular prodrug of floxuridine (FUDR)—poly(FUDR-ketal), engineered a micellar nanomedicine of FUDR, and intravenously co-administered the nanomedicine with the tumor-penetrating peptide iRGD for enhanced treatment of pancreatic tumor. A FUDR-derived mono-isopropenyl ether was synthesized and underwent self-addition polymerization to afford the hydrophobic poly(FUDR-ketal), which was subsequently co-assembled with amphiphilic DSPE-mPEG into the micellar nanomedicine with size of 12 nm and drug content of 56.8 wt% using nanoprecipitation technique. The acetone-based ketal-linked poly(FUDR-ketal) was triggered by acid to release FUDR to inhibit cell proliferation. In an orthotopic pancreatic tumor model derived from KPC (Kras LSL-G12D/+ ; Trp53 LSL-R172H/+ ; Pdx1-Cre) cells that overexpress neuropilin-1 (NRP-1) receptor, iRGD improved penetration of FUDR nanomedicine into tumor parenchyma and potentiated the therapeutic efficacy. Our nanoplatform, along with iRGD, thus appears to be promising for efficient penetration and activation of acid-responsive nanomedicines for enhanced pancreatic cancer therapy. [Display omitted] • An acid-activatable macromolecular prodrug of floxuridine was reported. • iRGD improved penetration of FUDR nanomedicine into parenchyma of pancreatic tumor. • iRGD potentiated anticancer efficacy of FUDR nanomedicine in KPC model. [ABSTRACT FROM AUTHOR]

Micelles are loosely bound aggregation of several tens or hundreds of atoms, ions or molecules, forming a colloidal particle. Micelles can either passively or actively target their payload to particular tissues in addition to dissolving hydrophobic medicines. Micelles nano-carriers hold the promise of solving the drug solubility issue among the various drug carriers that have been created. Gels are homogenous, semisolid preparations that often include one or more medications in the form of solutions or dispersions in appropriate hydrophilic or hydrophobic base. Now-a-days micellar gel can become promising approach for enhancing drug permeation through skin. Micellar gel shows higher penetration for treating deeply situated infections (example fungal infection). Micellar gel is generally prepared to increase the permeability or penetration of the medication across the skin. Micellar gels mainly used for providing hydrophobic medication which are encapsulated within micelles and deliver it to specific site. These benefits of micellar microparticles open up a lot of potential for the topical distribution of hydrophobic drugs in the future, with increased efficacy and lower production costs. There are several methods used for micelles and gel preparation such as dialysis method, solid dispersion method, microphase separation method, solvent evaporation method, thermal change method, chemical reaction and flocculation method. The characterization for micellar gel is particle size, critical micelles concentration, drug entrapment efficiency, drug content, nuclear magnetic resonance, differential scanning calorimetry, viscosity, spreadability, extrudability, patch test, skin irritation test and ex vivo skin permeability test. [ABSTRACT FROM AUTHOR]

This study aims to establish a facile, user-friendly, accurate, and repeatable spectrophotometric detection method for Cr(III) ions in trace quantities. The method utilises reagent 1-nitroso-2-naphthol (NNPh) in a sodium dodecyl sulphate (SDS) 1.0 % micellar solution, replacing the old, time-consuming, and expensive solvent extraction method that employs hazardous solvents such as carbon tetrachloride and chloroform. SDS surfactant is used to solubilise indissoluble chelates, making the proposed technique easy, rapid, and environmentally friendly. The established method exhibits an improved linear calibration range, sensitivity, limit of detection, and selectivity compared to earlier spectrophotometric methods employing different complexing agents. The stoichiometric ratio between Cr and NNP was observed to be 1 : 3. The molar absorption coefficient (ε) was determined to be 2.05 ∙ 104 l mol−1 cm−1 at λmax 579 nm. The limits of detection for Cr(III) was measured as 3.49 ng l −1. A calibration linear curve was achieved in the concentration range of 0.5–5.0 μgml−1. Results obtained showed good comparison with the results obtained by atomic absorption spectrometry. The developed method has been adapted for the analysis of Cr(III) in various alloys, pharmaceutical, environmental, and biological samples. [ABSTRACT FROM AUTHOR]

Despite the wide utility of micellar palladium (Pd) nanoparticle (NP)-catalyzed Mizoroki–Heck reactions in laboratory and industrial synthesis, the easy construction of micellar Pd NPs and the detailed role of surfactants remain the focus of attention. Here, we present a simple and sustainable strategy to construct a nanoreactor by connecting micelles with Pd NPs. This strategy enables us to obtain ultrasmall Pd NPs with an average particle size of 1.8 nm, mainly in situ synthesized by triethylamine (Et3N) reduction and stabilized by chelating with sugar-based surfactant micelles. The first-order kinetic model related to the initial concentration of Pd-based catalyst is established, and the apparent activation energy of this reaction in aqueous micellar solutions is calculated to be 40.49 kJ mol−1. The mechanism of the active species ultrasmall Pd(0) NPs obtained by the reductive elimination of Pd(II) precursors by base was demonstrated. Notably, the recycled aqueous reaction mixture containing the micelles and Pd NPs can be reused. [ABSTRACT FROM AUTHOR]

The fabrication of porous complex oxides with intriguing opto‐functional properties remains a challenge that requires innovative synthetic strategies. In this work, a facile soft template method is developed based on stable micellar solutions formed with lanthanide‐containing heteropolyoxomolybdate and alkaline earth citrates as metal salt precursors and block copolymer as templates. The resulting structures exhibit an effective interfacial Förster resonance energy transfer (IFRET) between the porous CaMoO4:Eu3+ (CEMO) host and the embedded surface‐active carbon dots through the conjugated bonds between Ca2+/Mo6+ cations and the C═O functional groups. Such IFRET process extends of Eu3+ absorption band toward the UV and blue regions, enabling the proof‐of‐concept demonstration of multiresponsive anticounterfeiting codes. The study not only presents a new strategy to prepare porous lanthanide‐doped complex oxides but also provides a feasible way to achieve spectral regulation through interfacial interaction for multifunctional luminescent materials. [ABSTRACT FROM AUTHOR]

Surfactant huff-n-puff (HnP) has been shown to be an effective protocol to improve oil recovery in tight and ultratight reservoirs. The success of surfactant HnP for enhanced oil recovery (EOR) process depends on the efficiency of the designed chemical formula, as the formation of an in situ microemulsion by surfactant injection is considered to be the most desirable condition for achieving an ultra-low interfacial tension during the HnP process. In this work, we conducted experimental studies on the mechanism of in situ microemulsion EOR in the Mahu tight oil reservoir. Salinity scan experiments were carried out to compare different surfactants with crude oil from the Mahu reservoir, starting with the assessment of surfactant micellar solutions for their ability to form microemulsions with Mahu crude oil and examining the interfacial characteristics. Subsequently, detailed micromodels representing millimeter-scale fractures, micron-scale pores, and nano-scale channels were utilized to study the imbibition and flowback of various surfactant micellar solutions. Observations of the in situ microemulsion system revealed the mechanisms behind the enhanced oil recovery, which was the emulsification's near-miscibility effect leading to microemulsion formation and its performance under low-interfacial-tension conditions. During the injection process, notable improvements in the micro-scale pore throat heterogeneity were observed, which improved the pore fluid mobility. The flowback phase improved the channeling between the different media, promoting a uniform movement of the oil–water interface and aiding in the recovery of a significant amount of the oil phase permeability. [ABSTRACT FROM AUTHOR]

Surfactant-assisted spontaneous imbibition is an important mechanism in enhanced oil recovery by capillary pressure in low permeability and tight oil reservoirs. Though many experiments have been conducted to study the mechanism of enhanced oil recovery by surfactant-assisted spontaneous imbibition, the effects of surfactant type, concentration, and temperature have not been well studied. Using tight sandstone outcrop core samples with similar permeability and porosity, this paper experimentally studies surfactant-assisted spontaneous imbibition using three different surfactant types, i.e., sodium dodecylbenzene sulfonate (SDBS), cocamidopropyl betaine (CAB), and C12–14 fatty alcohol glycoside (APG). In addition to the type of surfactant, the effect of the surfactant concentration and the temperature is also investigated. The study results show that the ultimate oil recovery of spontaneous imbibition with formation water and denoised water is about 10%. Surfactant can significantly improve the oil recovery of spontaneous imbibition by reducing the interfacial tension between oil and water, emulsifying crude oil and improving oil mobility. APG showed better performance compared to SDBS and CAB, with a maximum oil recovery factor of 36.19% achieved with formation water containing 0.05% APG surfactant. Lower concentrations (0.05% APG) in the formation water resulted in a higher oil recovery factor compared to 0.1% APG. Increasing temperature also improves oil recovery by reducing oil viscosity. This empirical study contributes to a better understanding of the mechanism of surfactant-assisted spontaneous imbibition and enhanced oil recovery in tight oil reservoirs. [ABSTRACT FROM AUTHOR]

The use of surfactants in oil recovery can effectively improve crude oil recovery rate. Due to the enhanced salt and temperature resistance of surfactant molecules by non-ionic chain segments, anionic groups have good emulsifying stability. Currently, there are many studies on anionic non-ionic surfactants for oil recovery in China, but there is relatively little systematic research on introducing EOs into hydrophobic alkyl chains, especially on their self-assembly behavior. This article proposes a simple and effective synthesis method, using 3-aminopropane sulfonic acid, fatty alcohol polyoxyethylene ether, and epichlorohydrin as raw materials, to insert EO into hydrophobic alkyl chains and synthesize a series of new anionic non-ionic Gemini surfactants (CnEO-5, n = 8, 12, 16). The surface activity, thermodynamic properties, and self-assembly behavior of these surfactants were systematically studied through surface tension, conductivity, steady-state fluorescence probes, transmission electron microscopy, and molecular dynamics simulations. The surface tension test results show that CnEO-5 has high surface activity and is higher than traditional single chain surfactants and structurally similar anionic non-ionic Gemini surfactants. Additionally, thermodynamic parameters (e.g., ΔG°mic ΔH°mic ΔS°mic et al. indicate that CnEO-5 molecules are exothermic and spontaneous during the micellization process. DLS, p-values, and TEM results indicate that anionic non-ionic Gemini surfactants with shorter hydrophobic chains (such as C8EO-5) tend to form larger vesicles in aqueous solutions, which are formed in a tail to tail and staggered manner; Negative non-ionic Gemini surfactants with longer hydrophobic chains (such as C12EO-5, C16EO-5) tend to form small micelles. The test results indicate that CnEO-5 anionic non-ionic Gemini surfactants have certain application prospects in improving crude oil recovery. [ABSTRACT FROM AUTHOR]

[Display omitted] Methyl 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. The 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. The 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. [ABSTRACT FROM AUTHOR]

The current work introduces the synthesis of inorganic salt nano/micro-crystals during the reduction of hydrogen tetrachloroaurate(III) by Pluronic triblock copolymers (P123, PEO20–PPO70–PEO20). The morphologies and component were confirmed using an electron microscope with an electronic differential system (EDS), and the crystal structures were determined with X-ray diffraction (XRD). The morphologies highly depend on the concentrations of Pluronic and pH values. The mean size of the nanocrystal and hollow micro-crystal were controlled typically in the range of 32–150 nm (side length) and 1.4 μm, respectively. Different from the electrospray–ionization (EI) method, a model in which KCl forms a supersaturated solution in the micellar core of Pluronic is used to explain the formation process. This work provides the new insight that inorganic salt nanocrystals could be synthesized with the template of micelles in pure aqueous solutions. [ABSTRACT FROM AUTHOR]

Despite their hazardous nature, carbonaceous particles (CPs) own very appealing properties, which make them a leading material in numerous applications. A systematic work on the properties of aqueous dispersions containing CPs, cetylpyridinium chloride (CPyCl), and sodium salicylate (NaSal) is here presented. Being CPs not soluble in water, an effective preparation method to obtain stable and homogeneous solutions was developed. Furthermore, a full characterization of the systems was performed by means of UV-Visible absorption spectroscopy, rheology, and interfacial tension measurements. Hydrophobic CPs are hard to disperse in a water matrix. The adoption of CPyCl as solubility enhancer was a sound strategy to finely disperse high concentration of CPs in an aqueous environment. The high CPs concentration involved conferred to the solutions a dark color and peculiar properties, such as UV and visible light radiation absorbance. The addition of NaSal to the CPyCl-CPs water solutions donated to the system robust viscoelasticity. We investigated 100 mM CPyCl aqueous solutions, with 60 and 70 mM NaSal, containing various amounts of CPs (0–9500 ppm). CPs at concentrations beneath 9500 ppm do not influence the system rheological properties. The well-known effect of NaSal on CPyCl solutions remains unaltered even in the presence of CPs at concentrations below 9500 ppm. On the other hand, the addition of 9500 ppm CPs provokes a moderate change in the rheological properties and microstructure of the systems. At a such high concentration, CPs seem to mimic the effect of NaSal on the micellar solutions, acting as a full-fledged hydrophobic salt. [ABSTRACT FROM AUTHOR]

Polymer nanocomposite materials with catalytic activity were designed via modification of MF-4SK ion-exchange membranes with Au and Ag nanoparticles obtained according to various synthetic methods in reverse micellar solutions. A sufficient transparency of the films allowed us to detect nanoparticles in the films using UV–Vis spectrophotometry, monitoring changes in the content of metal nanoparticles in the reverse micellar solution. A different mechanism of interaction of Au and Ag nanoparticles obtained by the same synthetic method with the MF-4SK film upon their contact with its surface was discovered, the destruction of nanoparticles was observed, and the influence of mechanism of primary acts in the formation of metal nanoparticles in reverse micellar solutions on their adsorption properties was confirmed. The highest concentration of gold nanoparticles was found in films immersed in reverse micellar solutions at the time of their exposure to ionizing radiation. [ABSTRACT FROM AUTHOR]

The physical properties of sodium cocoyl glycinate (SCG) and the synergistic effects within the SCG/CAPB complex system were investigated using visible–ultraviolet spectrophotometry and a surface tension meter. Analysis of the synergistic parameters of the complex system revealed that the combination of SCG and cocamidopropyl betaine (CAPB) yielded superior results compared to the individual use of SCG. Building upon this, the ternary phase behavior of the SCG/CAPB/H2O system was further explored. Different lyotropic liquid crystal phases were identified using polarized optical microscopy (POM) and small-angle X-ray scattering (SAXS). Surfactant solutions with varying mass fractions exhibited diverse phase behaviors, including the micellar phase (L1), micelle–solid mixed phase (L1-S), hexagonal phase (H), and lamellar phase (Lα), with the insoluble solid phase predominating. The investigation of the ternary phase diagram of SCG/CAPB/H2O provided valuable guidance for detergent formulation screening, enriched the understanding of sodium cocoyl glycinate complex systems, and further promoted the utilization of amino acid-based surfactants in the field of personal care products. [ABSTRACT FROM AUTHOR]

BACKGROUND: The biocompatible amphiphilic silk fibroin, extracted from domesticated silkworms, can adsorb at the oil--water interface and form elastic interfacial layers. In this study, three surfactants (cationic cetyltrimethylammonium bromide, the nonionic polyoxyethylene sorbitan monolaurate, and the anionic sodium dodecyl sulfate) were selected to investigate, through interfacial shear rheology, the influences of surfactants on the interfacial viscoelasticity and stability of silk fibroin at the interfaces between water and two different oils. RESULTS: The presence of surfactant prolongs the equilibration time and enhances the interfacial elastic modulus and toughness of the interfacial silk fibroin layers, especially at the nonpolar dodecane--water interface. However, when the surfactant exceeds a critical concentration, the shear modulus and stability of interfacial silk fibroin layers begin to decrease due to the competitive adsorption of surfactant molecules and the weakening of the protein network. Owing to electrostatic interactions, the ionic surfactants cetyltrimethylammonium bromide and sodium dodecyl sulfate can form more hydrophobic complexes with silk fibroin, which results in higher shear moduli than for silk fibroin and silk fibroin--polyoxyethylene sorbitan monolaurate mixture. CONCLUSION: Both the surfactant type and oil polarity play important roles in the adsorption, shear viscoelasticity, and stability of silk fibroin at the oil--water interface. Enhanced interactions between a silk fibroin--surfactant mixture and the oil phase delay the equilibration of the adsorption layers but strengthen the stability of interfacial layers. [ABSTRACT FROM AUTHOR]