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Thermodynamic hydrate promoters and kinetic hydrate promoters can be used to reduce the P–T conditions for clathrate hydrate synthesis to decrease the nucleation induction time while increasing growth rates. Two commonly used promoters for hydrate research are tetrahydrofuran (THF) and sodium dodecyl sulfate (SDS), which can increase the overall hydrate promotion when used in tandem as compared to individually. There are several molecular theories regarding how SDS promotes hydrate growth. This study explores the micellular theory, for which hydrate formation depends on surfactant aggregates (micelles) at a critical micelle concentration (CMC) to increase the interfacial surface area. The micellular theory is the most investigated and criticized surfactant hydrate promotion theory. To address questions related to micellar behavior, this study investigates the intermolecular behavior between SDS and THF for the identification of micelles at hydrate-forming conditions. The systems explored contained THF at 3 and 5 wt. % with varying concentrations of SDS below and above the CMC. Several methods including a qualitative visual method, conductivity, interfacial tensiometry, 13C Liquid-state Nuclear Magnetic Resonance (NMR) spectroscopy, and 1H diffusion NMR spectroscopy were evaluated at temperatures below the Krafft point of SDS and above 0 °C. The presence of THF at low concentrations decreased the critical temperature for the formation of SDS micelles, where SDS is solubilized in THF/water solution at hydrate-forming temperatures without precipitation. The CMC of SDS was decreased significantly even at hydrate-forming conditions. Mixed surfactant–cosolvent micellular behavior of SDS in the presence of low concentrations of THF was confirmed at hydrate-forming conditions above 0 °C. [ABSTRACT FROM AUTHOR]

Interfacial enhancements of chemical reaction equilibria and rates in liquid droplets are predicted using a combined theoretical and experimental analysis strategy. Self-consistent solutions of reaction and adsorption equilibria indicate that interfacial reactivity enhancement is driven primarily by the adsorption free energy of the product (or activated complex). Reactant surface activity has a smaller indirect influence on reactivity due to compensating reactant interfacial concentration and adsorption free energy changes, as well as adsorption-induced depletion of the droplet core. Experimental air-water interfacial adsorption free energies and critical micelle concentration correlations provide quantitative surface activity estimates as a function of molecular structure, predicting an increase in interfacial reactivity with increasing product size and decreasing product polarity, aromaticity, and charge (but less so for anions than cations). Reactions with small, neutral, or charged products are predicted to have little reactivity enhancement at an air–water interface unless the product is rendered sufficiently surface active by, for example, interactions with interfacial water dangling OH groups, charge transfer, or voltage fluctuations. [ABSTRACT FROM AUTHOR]

The critical micelle concentration (CMC) is a crucial parameter in understanding the self-assembly behavior of surfactants. In this study, we combine simulation and experiment to demonstrate the predictive capability of molecularly informed field theories in estimating the CMC of biologically based protein surfactants. Our simulation approach combines the relative entropy coarse-graining of small-scale atomistic simulations with large-scale field-theoretic simulations, allowing us to efficiently compute the free energy of micelle formation necessary for the CMC calculation while preserving chemistry-specific information about the underlying surfactant building blocks. We apply this methodology to a unique intrinsically disordered protein platform capable of a wide variety of tailored sequences that enable tunable micelle self-assembly. The computational predictions of the CMC closely match experimental measurements, demonstrating the potential of molecularly informed field theories as a valuable tool to investigate self-assembly in bio-based macromolecules systematically. [ABSTRACT FROM AUTHOR]

Hypothesis Atomistically-detailed models of surfactants provide quantitative information on the molecular interactions and spatial distributions at fluid interfaces. Hence, it should be possible to extract from this information, macroscopical thermophysical properties such as interfacial tension, critical micelle concentrations and the relationship between these properties and the bulk fluid surfactant concentrations. Simulations and Experiments Molecular-scale interfacial of systems containing n- dodecyl β -glucoside (APG 12) are simulated using classical molecular dynamics. The bulk phases and the corresponding interfacial regions are all explicitly detailed using an all-atom force field (PCFF+). During the simulation, the behaviour of the interface is analyzed geometrically to obtain an approximated value of the critical micelle concentration (CMC) in terms of the surfactant area number density and the interfacial tension is assessed through the analysis of the forces amongst molecules. New experimental determinations are reported for the surface tension of APG 12 at the water/air and at the water/ n -decane interfaces. Findings We showcase the application of a thermodynamic framework that inter-relates interfacial tensions, surface densities, CMCs and bulk surfactant concentrations, which allows the in silico quantitative prediction of interfacial tension isotherms. • We present a method to relate molecular observations to interfacial tensions. • Atomistic simulation results are provided for n -dodecyl β -glucoside; (APG 12). • New experimental determinations are reported for the water/air and water/ n -decane interfacial tension. • Consistency is seen between simulations, experiments and machine learning predictions. [ABSTRACT FROM AUTHOR]

BACKGROUND: The stem of Abroma augusta contains mucilaginous polysaccharides having numerous ethnomedicinal properties. The present work aimed to develop a scalable ultrasonic‐assisted aqueous Abroma augusta mucilage (AAM) extraction (UAE) method and further explores its emulsifying property and toxicity concern. RESULTS: The combination of ultrasonic power (750 W), solid‐to‐liquid ratio (1:15) and temperature (348 K) gave the highest extraction yield of 2.28% with a diffusivity value of 3.85 × 10−9 m2 s−1, which was higher than aqueous extraction method using a kinetic model based on Fick's second law of diffusion. The extracted polysaccharide showed no toxicity as measured through 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assay on RAW cell line. Additionally, the polysaccharide over its critical micelle concentration (400, 500, 600 and 700 μg mL−1) offered emulsifying properties with 0.5%, 1% and 5% oil (v/v). The emulsion with a polysaccharide concentration of 600 μg mL−1 with 5% oil (v/v) provides stability against coalescence for 3 days. CONCLUSION: The overall findings indicated that UAE of AAM polysaccharide can be used for an efficient extraction method, and the obtained polysaccharide is nontoxic in nature and bears emulsifying properties. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In this work, the physiochemical properties of the drug, isoproterenol hydrochloride, were analyzed in the presence of β-cyclodextrin in an aqueous medium to gain a better understanding of the prevailing interactions among solute–solvent systems with the help of viscosity and conductivity studies. From viscosity measurements, the viscosity B -coefficient along with its transfer parameter was calculated using the Jones–Dole equation. In addition to this, the activation parameters such as Δ μ 1 o # , Δ μ 2 o # , Δ S 2 o # , and Δ H 2 o # were evaluated and discussed to gain a better understanding of the mechanism of viscous flow in terms of transition state theory. Along with this, conductivity studies were performed to investigate the thermodynamics of the ternary system in terms of changes in Gibbs free energy. Also, the delayed critical aggregate concentration of the ternary system supports favourable interaction between the studied drug and β-cyclodextrin molecules. [ABSTRACT FROM AUTHOR]

Polyelectrolytes are used in different technology systems, such as reducing environmental pollution, producing lithium batteries, achieving better performance, and prolonging half-life. One of the vital applications of polyelectrolytes is in drug delivery systems as a drug carrier to reach the specific desired target organ and increase drug effectiveness. To find and reach the optimum complex of polyelectrolytes in the context of drug delivery systems, we used Luminescence spectroscopy, viscosimetry, and conductivity methods in different concentrations, pH, and temperatures to find the polyelectrolyte's behavior in cationic and anionic polymers besides copolymers. In this study, Polyallylamine P(AlAm), polyallylamine hydrochloride P(AlAm.HCl), polyvinyl sulfonic acid P(VSA), and copolymer (32:68) actual composition are investigated. The hydrophobicity of the polymer is prominent at higher pH with P(AlAm.HCl). A more hydrophilic polymer is produced by forming the NH3+ ions at lower pH. P(AlAm) hydrophobicity is determined at higher pH, and hydrophilicity happens at low pH. The temperature has now not affected the polymer's hydrophilicity and hydrophobicity. Increasing and lowering pH from 4.5 has not revealed a substantial P(VSA) change. The temperature and pH no longer affect the copolymer. We prepared complex formation of P(AlAm.HCl), P(AlAm), P(VSA), and copolymer with anionic surfactant sodium dodecylbenzene sulfonate (SDBS) in under and above critical micelle concentration (CMC) value. Excellent complexation is obtained among P(AlAm.HCl) and SDBS using Luminescence spectroscopy. Moreover, the viscosity behavior of P(AlAm.HCl) and P(AlAm) in pure water and 0.5 M NaCl solution is investigated. The polyelectrolyte properties of P(AlAm.HCl) are lots better than P(AlAm). That is confirmed using the Luminescence and conductivity method in different pH values. [ABSTRACT FROM AUTHOR]

At T = (278.15–318.15) K and atmospheric pressure, Hepler’s constant values, (∂2VB/∂ T2)P, and apparent molar expansivities (Eφ) were calculated using the temperature dependence of apparent molar volumes (VB). Because of the increase in hydrophobic hydration of tetramethylpiperidine 1-oxyl-based ionic liquids (TILs), the Hepler’s constant values were found to change from positive to negative, indicating that the TILs under consideration changed primarily from structure-promoting to structure-breaking. The critical micelle concentration of conductivity (CMC) was calculated based on experimental conductivity, which reflects the dissociation and the interaction and aggregation behaviour of TILs. [ABSTRACT FROM AUTHOR]

This document presents a study on the ultrasensitive detection of pathological protein aggregates associated with neurodegenerative diseases. The study focuses on a reagent called Brij-58, which enhances the seed amplification assay (SAA) without inhibiting it. The researchers found that Brij-58 significantly increased the sensitivity of detecting TAR DNA-binding protein 43 (TDP-43) seed fibrils in patient-derived brain tissues. The study suggests that Brij-58 has the potential to be used in the early diagnosis and monitoring of neurodegenerative diseases. However, further research is needed to apply these findings in clinical practice. [Extracted from the article]

BACKGROUND: Walnut protein (WP) is recognized as a valuable plant protein. However, the poor solubility and functional properties limit its application in the food industry. It is a great requirement to improve the physicochemical properties of WP. RESULTS: Following a 90 min restricted enzymatic hydrolysis period, the solubility of WP significantly increased from 3.24% to 54.54%, with the majority of WP hydrolysates (WPHs) possessing a molecular weight exceeding 50 kDa. Circular dichroism spectra showed that post‐hydrolysis, the structure of the protein became more flexible, while the hydrolysis time did not significantly alter the protein's secondary structure. After hydrolysis, WP's surface hydrophobicity significantly increased from 2279 to 6100. Furthermore, WPHs exhibited a strong capacity for icariin loading and micelle formation with critical micelle concentration values of 0.71, 0.99 and 1.09 mg mL−1, respectively. Moreover, similar immuno‐enhancement activities were observed in WPHs. After exposure to WPHs, the pinocytosis of RAW264.7 macrophages was significantly improved. WPH treatment also increased the production of nitric oxide, interleukin‐6 (IL‐6) and tumor necrosis factor‐α (TNF‐α) in macrophages. Up‐regulation of mRNA expressions of IL‐6, inducible nitric oxide synthase (iNOS) and TNF‐α was observed in a dose‐dependent manner. CONCLUSION: The enhancement of functionality and bioactivity in WP can be achieved through the application of limited enzyme digestion with trypsin. This process effectively augments the nutritional value and utility of the protein, making it a valuable component in various dietary applications. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In this paper, a series of cationic polyurethane fluorinated surfactants were synthesized using a series of isocyanates, and 1H, 1H, 2H,2H-tridecafluoro-1-octanol, 2-(dimethylamino)ethanol, and iodomethane as raw materials in a three-step sequential reaction. These fluorinated surfactants exhibited high surface activity and low critical micelle concentration. In addition, these fluorinated surfactants exhibited excellent wetting and emulsification properties at very low concentrations of 0.1 wt%. In addition the cationic polyurethane fluorinated surfactants are compounded into aqueous film-forming foam extinguishing agents, which exhibit excellent fire extinguishing properties. The desirable properties coupled with the simple and green preparation process make this strategy a new way to prepare sustainable alternatives to long fluoroalkyl chain surfactants. A new degradable cationic fluorocarbon surfactant prepared by coupling isocyanate and hydroxyl group was developed and applied to fire fighting. [ABSTRACT FROM AUTHOR]

BACKGROUND: The oil industry has a big impact on the environment by itself and by using chemically synthesized surfactants. Biosurfactants are an ecofriendly alternative, especially rhamnolipids produced by Pseudomonas aeruginosa. Rhamnolipids in a determined concentration decrease the liquid surface tension, and this allows access oil hydrocarbon to be degraded. The objective of this research is to characterize the biosurfactant produced by the native strain P. aeruginosa 6K‐11 by determining its critical micelle concentration (CMC), Krafft point, and emulsifying activity. RESULTS: Experiments were initially performed with rhamnolipid produced by P. aeruginosa 6K‐11 growing on Siegmund‐Wagner medium with 1% of waste oil as carbon source and at 31.26 °C, 186 rpm after 42 h of incubation. After that, the biosurfactant was purified according to acid precipitation methodology. The first conductivity measurement, 34 μS/cm, was obtained with 12.5 g/L of rhamnolipid by using an APERA conductivity meter. The rhamnolipid CMC was 5.86 g/L due to the conductivity measurements graph and 0.49 was the dissociation degree. The equations of both lines were found by the method of least squares. The rhamnolipid has produced 1.97 Units of Emulsifying Activity (UEA) and 50% stability was observed based on the E24 Index. The highest conductivity achieved under 39 °C, as calculated from a conductivity against temperature graph, was the Krafft point. CONCLUSION: These findings give important parameters to characterize the P. aeruginosa 6K‐11 biosurfactant activity that can be used to accelerate oil biodegradation in bioremediation processes. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Exploring the optimal experimental conditions and mechanism of a novel functionalized ionic liquid 1-ethyl-3-methylimidazolium bromide ([EMIM][Br]) for enhancing the wettability of coal powder is of great significance for reducing the harm of coal dust. This study determined the critical micelle concentration of [EMIM][Br] aqueous solution through ultraviolet(UV) absorption spectroscopy, and analyzed the mechanism of the influence of [EMIM][Br] aqueous solution on the wettability of coal using characterization methods such as contact angle, scanning electron microscope(SEM), automated surface area and porosity analyzer(BET), and fourier transform infrared spectroscopy(FTIR). The results showed that the critical micelle concentration of [EMIM][Br] aqueous solution was 0.005 mol/L, and the optimal experimental conditions were reaction temperature of 40°C, soaking time of 8 hours, and ratio of 1 g to 20 ml. After the action of [EMIM][Br] aqueous solution, the coal dust stomatal layer zone was developed, wedge-shaped stomata and sheet-filled cracks appeared, and the number of mesopores was increased. The content of hydrophilic functional groups such as C–O, carboxyl(–COOH), hydroxyl ether hydrogen bonds(OH...O), and hydroxyl self-consolidating hydrogen bonds(OH...OH) in the pulverized coal was increased, and the content of hydrophobic functional groups such as aryl hydrocarbons –CH3 and–CH2 was decreased, which improved the wettability of the pulverized coal. [ABSTRACT FROM AUTHOR]

Erythorbyl oleate (EO), a novel emulsifier with multifunctional properties, was synthesized via lipase‐catalyzed solvent‐free esterification between erythorbic acid and oleic acid. The reaction produced EO of 30.75 ± 1.65 mM at 60 h, monitored by high‐performance liquid chromatography (HPLC) analysis. Purified EO was chemically identified as 6‐O‐oleoyl‐erythorbic acid by HPLC‐electrospray ionization/mass spectrometry (ESI‐MS), 1H nuclear magnetic resonance (NMR), and 13C NMR analyses, and further investigations on its multifunctionalities were conducted. EO displayed antioxidant activity equivalent to erythorbic acid in 2,2‐diphenyl‐1‐picrylhydrazyl and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) radical scavenging activities. Investigation of the antibacterial activity of EO against foodborne pathogens showed MICs of 0.27 ± 0.09 and 0.40 mM for Bacillus cereus ATCC 10876 and Staphylococcus aureus ATCC 12692, respectively. EO also displayed interfacial properties, lowering interfacial tension between medium‐chain triglyceride oil and water to 3.40 ± 0.04 mN/m with a critical micelle concentration of 2.54 ± 0.03 mM. Dynamic light scattering analyses of the emulsion stabilized by EO demonstrated a similar polydispersity index (0.15 ± 0.00) to Tween 80‐stabilized emulsion (0.28 ± 0.01), with an average droplet size of 173.2 ± 1.8 nm. In addition, the EO‐stabilized emulsion exhibited a negative surface charge (−56.83 ± 4.30 mV) in zeta potential measurements, indicating sufficient electrostatic repulsion between droplets. These results suggest that EO is a multifunctional emulsifier to simultaneously control oxidative rancidification and bacterial spoilage in emulsion‐based foods.Practical Application: EO was synthesized via an enzymatic esterification reaction between erythorbic acid and oleic acid. The synthetic process excluded any use of organic solvent, diminishing potential health hazards or environmental pollution associated with chemical reactions. The interfacial properties of the resultant EO, along with excellent antioxidant and antibacterial activities, propose its potential application in emulsion‐based foods. Simultaneous control of bacterial spoilage and oxidative rancidification by EO would fulfill the industrial needs for extending shelf life and enhancing consumer safety. [ABSTRACT FROM AUTHOR]

Short‐chain fluorocarbon surfactants grafted with alcohol, carboxyl and ester functional groups were prepared by quaternization with short‐chain perfluorobutyl sulfonyl fluoride as raw material. The structures of surfactants were characterized by infrared spectroscopy, nuclear magnetic resonance and mass spectrum. The surface activity, micelle formation process and micelle aggregation behavior of surfactants were studied by surface tensiometer, dynamic light scattering particle size analyzer and fluorescent spectrophotometer. The results show that the critical micelle concentration (CMC) of surfactants are 19.3, 7.8 and 2.2 mmol L−1, and the surface tension of the surfactant solution at CMC are as low as 17.3, 19.2 and 18.5 mN m−1, respectively. The standard Gibbs free energy (ΔGm0 ${\Delta G_{\rm{m}}^0 }$) values of surfactants are negative, and the absolute values of ΔGm0 ${\Delta G_{\rm{m}}^0 }$ are less than the standard Gibbs adsorption energy (ΔGa0 ${\Delta G_{\rm{a}}^{\rm{0}} }$), illustrating that the adsorption process is easier than the micelle formation process. In addition, the size distribution of the aggregates is much larger than that of spherical micelles, showing that the surfactant self‐assembled into larger aggregates in solution. The grafted hydrophilic functional groups show a significant effect on the performance of surfactants. The ester‐based surfactant has a lower CMC value, which has the advantages of small dosage, good economy and excellent application value. [ABSTRACT FROM AUTHOR]

Electrical conductimetry and dynamic light scattering (DLS) were used to investigate the aggregation behaviors of four amino acid-based surfactants (AABSs; undecanoyl-glycine, undecanoyl-l-alanine, undecanoyl-l-valine, undecanoyl-l-leucine) in the presence of five linear diamine counterions (1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane). Electrical conductimetry was used to measure the CMCs for each system, which ranged from 5.1 to 22.5 mM. With respect to counterions, the obtained CMCs decreased with increases in the interamine spacer length; this was attributed to the improved torsional binding flexibility in longer counterions. Strong linear correlations (mean R2 = 0.9443) were observed between the CMCs and predicted surfactant partition coefficients (logP; water/octanol), suggesting that micellization is primarily driven by the AABS's hydrophobicity for these systems. However, significant deviations in this linear relationship were observed for systems containing 1,2-diaminoethane, 1,4-diaminobutane, and 1,6-diaminohexane (p = 0.0774), suggesting altered binding dynamics for these counterions. pH measurements during the CMC determination experiments indicated the full deprotonation of the AABSs but did not give clear insights into the counterion protonation states, thus yielding an inconclusive evaluation of their charge stabilization effects during binding. However, DLS measurements revealed that the micellar size remained largely independent of the counterion length for counterions longer than 1,2-diaminoethane, with hydrodynamic diameters ranging from 2.2 to 2.8 nm. This was explained by the formation of charge-stabilized noncovalent dimers, with each counterion bearing a full +2 charge. Conductimetry-based estimates of the degrees of counterion binding (β) and free energies of micellization (ΔG°M) revealed that bulky AABSs exhibit preferential binding to counterions with an even number of methylene groups. It is proposed that when these counterions form noncovalent dimers, perturbations in their natural geometries result in the formation of a binding pocket that accommodates the AABS steric bulk. While the direct application of these systems remains to be seen, this study provides valuable insights into the structure–property relationships that govern AABS aggregation. [ABSTRACT FROM AUTHOR]

AbstractAsymmetric gemini surfactants were synthesized by the quaternization reaction of 1-(2-hydroxypropyl)-4-ethyl piperazine with (C9, C10, C12, and C14) alkyl bromides. The surface tension of their aqueous solutions was determined by the Du Nouy ring method and the conductometric method of specific electrical conductivity. According to the concentration dependence graphs of surface tension and specific electrical conductivity, critical micelle concentration – CMC, degree of association of the counterion – β, surface area occupied by the head group of the surfactant – Amin, maximum surface excess concentration – Γmax, effectiveness or surface pressure –πCMC, adsorption efficiency – pC20 were calculated, and the change of these parameters depending on the length of the alkyl chain was determined. Simultaneously, variations in Gibbs free energies of micellization and adsorption processes were computed. The diameters of aggregates formed by asymmetric gemini surfactants in water were determined by the DLS method. Antimicrobial abilities of asymmetric gemini surfactants against gram positive and gram negative bacteria and fungi were defined by the disk diffusion method. [ABSTRACT FROM AUTHOR]

In this study, three Gemini cationic surfactants related to thiazol-2-amine with three hydrocarbon chain lengths including 3-hexylthiazol-3-ium (TAC6), 3-dodecylthiazol-3-ium (TAC12) and octadecylthiazol3-ium (TAC18) were prepared. Surfactant structures were confirmed with IR and 1HNMR Spectroscopies. Critical micelle concentrations for all surfactants in 15% DMSO-Water solvent were measured using conductometric, refractometric, and densitometric techniques. Thermodynamics parameters were computed and explained. Also, enhancing properties of all surfactants were indicated under the effect of two concentrations, 0.001 M and 0.01 M, of six inorganic salts including Cl−, Br−, I−, Co+2, Cu+2, and Mn+2 radicals using conductivity and refractive index measurements. All techniques used to measure critical micelles concentration showed a good convergence in measuring CMC values and the behavior of all surfactants in 15% DMSO-water solvent. Increasing the binding constant of the counter ion and association constant reflects the effect of hydrocarbon chain length increment on enhancing micelle formation, where TAC 18 was shown as the lowest CMC in all applied measurements. Modeling the density of all surfactant solutions under study indicates an increase in hydrophobic polarizability with an increase in the molecular weight of the surfactant. Inorganic salts decreased the CMC of all surfactants with the increase in Gibbs free energy of micellization which ensures easier formation of more stable micelles in the presence of a salt solution. The effect of salts on decreasing CMC for all surfactants under study was arranged in the following order: Mn+2 < Cu+2 < Co+2 for cationic radicals and I− < Br− < Cl− for anionic radicals. [ABSTRACT FROM AUTHOR]

Introduction: The ability to produce biosurfactants plays a meaningful role in the bioavailability of crude oil hydrocarbons and the bioremediation efficiency of crude oil-degrading bacteria. This study aimed to characterize the produced biosurfactants by Pseudomonas oryzihabitans during the biodegradation of crude oil hydrocarbons. Methods: The biosurfactants were isolated and then characterized by Fourier transform infrared (FTIR), liquid chromatography-mass-spectrometry (LC-MS), and nuclear magnetic resonance spectroscopy (NMR) analyses. Results: The FTIR results revealed the existence of hydroxyl, carboxyl, and methoxyl groups in the isolated biosurfactants. Also, the LC-MS analysis demonstrated a main di-rhamnolipid (l-rhamnopyranosyll-rhamnopyranosyl-3- hydroxydecanoyl-3-hydroxydecanoate, Rha-Rha-C10-C10) along with a monorhamnolipid (l-rhamnopyranosyl-b-hydroxydecanoylb-hydroxydecanoate, Rha-C10-C10). In agreement with these findings, the NMR analysis confirmed the aromatic, carboxylic, methyl, sulfate moieties, and hexose sugar in the biosurfactants. The emulsion capacity of the biosurfactants decreased the surface tension of the aqueous system from 73.4 mN m-1 to around 33 mN m-1 at 200  mg  L-1 as the critical micelle concentration. The emulsification capacity of the biosurfactants in the formation of a stable microemulsion for the diesel-water system at a wide range of pH (2-12), temperature (0-80°C), and salinity (2-20  g  L-1 of NaCl) showed their potential use in oil recovery and bioremediation through the use of microbial enhancement. Discussion: This work showed the ability of Pseudomonas oryzihabitans NC392 cells to produce rhamnolipid molecules during the biodegradation process of crude oil hydrocarbons. These biosurfactants have potential in bioremediation studies as eco-friendly and biodegradable products, and their stability makes them optimal for areas with extreme conditions. [ABSTRACT FROM AUTHOR]

China's low-permeability reservoirs possess abundant resources characterized by poor rock properties, strong heterogeneity, and fine pore throats, leading to low displacement efficiency. This study expands the concentration window for achieving ultra-low interfacial tension (ULT) by adding co-surfactants to the primary surfactant. Research indicates that the critical micelle concentration (cmc) and corresponding interfacial tension (γcmc) of the compounded system are lower than those of individual components. When the molar ratio of M to Q is 1:1, the interaction parameter βm reaches its minimum value, indicating the strongest synergistic effect within the system. The compounded system achieves an oil-water interfacial tension as low as 0.0021 mN/m at 0.25% M + 0.025% Q, enhancing recovery efficiency by 0.88% compared to the single component M. Utilizing micro-etching microscopy and natural core physical model experiments, the compounded surfactant system's recovery efficiency increment reaches 19.7%, significantly surpassing water flooding effects. This provides robust support for the efficient development of the Jiyuan X reservoir. [ABSTRACT FROM AUTHOR]

Surfactants are hailed as "industrial monosodium glutamate", and are widely used as emulsifiers, demulsifiers, water treatment agents, etc., in the petroleum industry. However, due to the unidirectivity of conventional surfactants, the difficulty in demulsifying petroleum emulsions generated after emulsification with such surfactants increases sharply. Therefore, it is of great significance and application value to design and develop a novel switchable surfactant for oil exploitation. In this study, a CO2-switchable Gemini surfactant of N,N′-dimethyl-N,N′-didodecyl butylene diamine (DMDBA) was synthesized from 1, 4-dibromobutane, dodecylamine, formic acid, and formaldehyde. Then, the synthesized surfactant was structurally characterized by infrared (IR) spectroscopy, hydrogen nuclear magnetic resonance (1H NMR) spectroscopy, and electrospray ionization mass spectrometry (ESI-MS); the changes in conductivity and Zeta potential of DMDBA before and after CO2/N2 injection were also studied. The results show that DMDBA had a good CO2 response and cycle reversibility. The critical micelle concentration (CMC) of cationic surfactant obtained from DMDBA by injecting CO2 was 1.45 × 10−4 mol/L, the surface tension at CMC was 33.4 mN·m−1, and the contact angle with paraffin was less than 90°, indicating that it had a good surface activity and wettability. In addition, the kinetic law of the process of producing surfactant by injecting CO2 was studied, and it was found that the process was a second-order reaction. The influence of temperature and gas velocity on the reaction dynamics was explored. The calculated values from the equation were in good agreement with the measured values, with a correlation coefficient greater than 0.9950. The activation energy measured during the formation of surfactant was Ea = 91.16 kJ/mol. [ABSTRACT FROM AUTHOR]

Three kinds of multiblock polyethylene oxide-polypropylene oxide (PEOm-PPOn for short) were synthesized using ethylene glycol as the initiated core via the living anionic polymerization. Respectively, the multiblock polyethers were named E340, E540, and E740 based on the block number (3, 5, 7) and the content of ethylene oxide (EO, 40 wt%), which were confirmed by the Fourier transform infrared (FT-IR), hydrogen nuclear magnetic resonance (1H NMR), and gel permeation chromatography (GPC). Moreover, their bulk and solution properties, including dynamic modulus, rheological characteristic, viscosity, aggregation behavior, surface tension, steady-state fluorescence, solubility, and microemulsion performance were determined. The test results of rheological properties showed that these multiblock copolyethers behaved as the pseudo-plastic non-Newtonian fluids. Furthermore, it was found that their solubility and surface tension were gradually decreased with an increase of block numbers. Nevertheless, the dynamic modulus tended contrary trends. Research on the aggregation and micro-emulsion properties in aqueous solutions indicated that the value of critical micelle concentration (CMC) increased, and meanwhile the ability of solubilization and micro-emulsion formation deteriorated with increasing block numbers. In conclusion, their aggregation mechanism in aqueous solution was also given. [ABSTRACT FROM AUTHOR]

Mineral slurry preparation and pipeline transport require careful particle size distribution and additive selection to ensure cost-effective and reliable transportation. The research described here was aimed to better understand the flow behavior of a limestone sample by combining coarse and fine particles and a low-cost natural additive, Saponin, derived from Sapindus laurifolia. Four distinct bi-modal suspension samples were formed using various mixtures of limestone samples with sizes varying from 0–53 and 75–106 µm. The rheological characteristics of the suspension were investigated at shear rates of 50 to 500 s−1 for solid concentrations 40–70% by weight. The additive's critical micelle concentration was found to be 1.8 weight percent. The Hershel-Bulkley model fits the experimental data the best. The appropriate proportion of coarse particles was discovered to be 30% based on critical factors such as apparent viscosity and pressure drop. The addition of the surfactant reduced the surface tension, increased the wettability, and decreased the particle-particle interaction to stabilize the limestone-water suspension. [ABSTRACT FROM AUTHOR]

Indocyanine green (ICG), the only near-infrared (NIR) dye approved for clinical use, has received increasing attention as a theranostic agent wherein diagnosis (fluorescence) is combined with therapy (phototherapy), but suffers rapid hepatic clearance, poor photostability, and limited accumulation at tumor sites. Here we report that dimerized ICG can self-assemble to form zwitterionic nanoparticles (ZN-dICG), which generate fluorescence self-quenching but exhibit superior photothermal and photodynamic properties over ICG. The zwitterionic moieties confer ZN-dICG an ultralow critical micelle concentration and high colloidal stability with low non-specific binding in vivo. In addition, ZN-dICG can respond to the over-generated reactive oxygen species (ROSs) and dissociate to restore NIR fluorescence of ICG, amplifying the sensitivity via albumin binding for low-background imaging of tumors. Following systemic administration, ZN-dICG accumulated in tumors of xenograft-bearing mice for imaging primary and metastatic tumors, and induced tumor ablation under laser irradiation. The discovery of ZN-dICG would contribute to the design of translational phototheranostic platform with high biocompatibility. Indocyanine green (ICG) has been extensively studied as a phototheranostic agent that combines imaging with phototherapies, but it suffers from rapid hepatic clearance, poor photostability, and limited accumulation at tumor sites. Here, we report a strategy to construct ICG dimers (ICG-tk-ICG) by conjugating two ICG molecules via a thioketal bond, which can self-assemble into zwitterionic nanoparticles (ZN-dICG) at ultralow critical micelle concentrations, exhibiting superior photothermal and photodynamic properties over ICG. ZN-dICG responds to the over-generated ROS in tumors and dissociates to restore the NIR fluorescence of ICG, enhancing the sensitivity via albumin binding for low-background imaging of tumors. This study offers a supramolecular strategy that may potentiate the clinical translation of ICG in imaging-guided cancer phototherapy. [Display omitted] [ABSTRACT FROM AUTHOR]

Amphiphilic block copolymers, made of biocompatible polycaprolactone (PCL) and polyethylene glycol (PEG), due to their ability to self‐assemble in water into nanoscopic micelles, have been largely exploited for drug delivery systems (DDS). This study introduces a novel approach by synthesizing a fluorescein isothiocyanate FITC‐labelled PCL‐PEG‐PCL triblock copolymer, with the aim to develop a drug delivery system for natural bioactive. As a proof of concept, the FITC‐labelled PCL‐PEG‐PCL copolymer is applied for the preparation of micelles encapsulating into the core capsaicin (CP), a pungent alkaloid found in chili peppers with diverse therapeutic applications. Challenges associated with CP′s solubility, bioavailability, and stability are addressed using this DDS. Comprehensive characterization of FITC‐labelled copolymer is conducted using a range of analytical techniques, including nuclear magnetic resonance (NMR), dynamic light scattering (DLS), high‐performance liquid chromatography (HPLC), Fourier‐transform infrared spectroscopy (FTIR), fluorescence, and confocal laser scanning microscopy (CLSM). Key properties such as critical micelle concentration, CP loading, and release behavior are thoroughly investigated and compared with the characteristics of the unlabeled parent copolymer. This research pioneers the investigation of PCL‐PEG‐PCL triblock copolymers for CP delivery, along with the use of FITC‐labelled variants, opening new avenues for research in drug delivery and nanomedicine. [ABSTRACT FROM AUTHOR]

This study investigates the effects of sodium dodecyl sulfate (SDS) and polyethylene glycol (PEG) on the galvanic corrosion behavior of copper (Cu) coupled to gold (Au) in a printed circuit board (PCB) etching solution. Galvanic corrosion tests using ZRA (zero resistance ammeter) were performed to determine the optimal SDS concentration for corrosion inhibition. The corrosion current between Cu and Au decreased significantly with the addition of SDS, from 3.26 mA/cm2 to 0.248 mA/cm2 at 4 mM SDS, achieving an inhibitor efficiency (IE) of 92.3%. However, at 15 mM SDS, the corrosion current increased, and IE decreased to 80.5%. This phenomenon is attributed to the critical micelle concentration (CMC) of SDS, where surfactant molecules aggregate and reduce surface adsorption properties. Similarly, ZRA tests were conducted to analyze the effects of PEG on galvanic corrosion. The corrosion current significantly decreased with PEG addition, achieving 98.1% IE at 1 g/L and 99.5% IE at 2 g/L. Beyond this concentration, no significant change in IE was observed, indicating saturation. Potentiodynamic polarization tests were also conducted to study the individual effects of SDS and PEG on Cu and Au. The results showed that SDS effectively inhibited Cu corrosion but had a minimal impact on Au. In contrast, PEG significantly reduced the corrosion current density for both Cu and Au, with reductions of 99.5% and 95.1%, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] Antimicrobial resistance (AMR) is a pressing global health concern. ESKAPEE pathogens, such as Methicillin-resistant Staphylococcus aureus (MRSA) are notable of concern in healthcare settings due to their resistance to critical antibiotics. To combat AMR, the development of alternatives such as bacterial membrane-active agents is crucial. Fatty acids (FAs) have emerged as a sustainable, antibiotic-free solution with inherent antibacterial activity. However, long chain saturated fatty acids (LCFAs) sodium soaps exhibit poorly antibacterial properties in comparison to short chain FAs, believed to be linked to limited solubility in aqueous media. We employed choline as a chaotropic organic counter-ion to enhance the solubility of LCFAs and investigated their antibacterial effects against MRSA. The optimal medium conditions for micelle formation for LCFAs was first investigated. Then, we determined the critical micelle concentration (CMC), micellar morphology, and aggregation number through surface tension measurements and small angle neutron scattering experiments. Antimicrobial activity was assessed using minimum bactericidal concentration (MBC) assays and time-kill experiments. We have identified conditions where LCFAs are effective against MRSA for the first time, providing valuable insights for developing new antibacterial agents to fight AMR. LCFAs need to be used above their Krafft temperatures and CMC to exhibit antibacterial efficacy. [ABSTRACT FROM AUTHOR]

[Display omitted] Lysopalmitoylphosphatidylcholine (LysoPC) is a soluble single-chain surfactant product of the innate immune system degradation of double-chain phospholipids. LysoPC adsorption to the air–water interface in lung alveoli can be modeled using alveolar-sized bubbles of constant surface area in a capillary pressure microtensiometer to show that adsorption is diffusion limited both below and above the critical micelle concentration (CMC). Above the CMC, a local equilibrium model is proposed in which depletion of the local monomer concentration drives dissociation of micelles in a region near the bubble surface. A capillary pressure microtensiometer in which a feedback loop maintains a constant bubble radius and surface area is used to measure dynamic surface tension during LysoPC adsorption. Direct numerical solution of the spherical diffusion equations, a new three parameter virial equation of state for interface thermodynamics, and a local equilibrium model of micellization above the CMC are used to accurately model the dynamic surface tension experiments both below and above the LysoPC CMC. LysoPC adsorption is shown to be diffusion-limited over concentrations ranging from below to well above the CMC, and to be well described by a local equilibrium model at concentrations above the CMC. Modelling the dynamic surface tension provides a reliable estimate of the micelle diffusivity near the CMC that is difficult to obtain by other methods in systems with low CMCs. [ABSTRACT FROM AUTHOR]

The objective of this study is to utilize cost-effective renewable substrates derived from agro-food wastes for the production of biosurfactant by Bacillus megaterium, which was isolated from petroleum sludge. Various agro-food waste materials, namely potato peelings (PP), rice cooking water (RW), biscuit by products (BB), carob pods (CP), and eggshells, were evaluated as nutrient sources for bacterial growth compared to a synthetic medium (SM). The results indicate that the medium comprising carob pods, potato peels supplemented with eggshells promoted the growth of the bacteria and the production of Biosurfactants at a rate of 150 mg/l and 140 mg/l respectively. The biosurfactant exhibited an emulsification index (E24) of 55.23 ± 0.32%, 46.47 ± 3% 43.80 ± 0.4%, 18.33 ± 0.25% and 20 ± 0.11% for PP, CP, SM, BB and RW respectively. The biosurfactant produced from PP had the ability to decrease the surface tension of water from 74 to 39.38 mN/m, with a critical micelle concentration (CMC) of 15 mg/L. The chemical characterization of purified biosurfactant was done using Fourier-transform infrared spectroscopy (FTIR) and Thermal gravity (TG), as well as differential scanning calorimetry (DSC) analysis (TG/DSC), revealing the functional groups and thermostability of the biosurfactant. The DSC spectrum for PP biosurfactant showed the highest thermostability with crystalline temperature (Tc) of 150 °C and melting point (Tm) of 295 °C. The extracted biosurfactant was mixed with petroleum sludge, composed of heavy oil, 40.64 ± 0.19% of extracted oil was obtained after 5 h of reaction while using PP based medium. [ABSTRACT FROM AUTHOR]

In this investigation, cationic surfactant cetyltrimethylammonium chloride (CTAC)-modified nanofiltration (NF) membranes were investigated for sodium diclofenac (DFS) removal from aqueous solution. The effects of CTAC incorporation on the membranes at various concentrations below, at, and above the critical micelle concentration (CMC) were evaluated in terms of membrane permeability, morphology, antifouling properties, and performance. CTAC-modified membranes exhibited enhanced structural properties, increased hydrophilicity, higher pure water flux (461 L/m2 h), and superior antifouling resistance (98% BSA protein rejection, 82.1% FRR). Consequently, the optimized 0.1 wt% CTAC-modified membrane at CMC concentration exhibited superior rejection efficiency compared to the unmodified membrane, increasing from 35.62 to 65.17% for sodium diclofenac removal. The findings of this study demonstrate that the optimized membrane exhibited the best performance in all parameters, making it suitable for practical application in the removal process of sodium diclofenac.Highlights: Cationic surfactant were used to modify the NF membrane in three concentrations of CMC, above CMC and below CMC. Reactive cationic surfactant was used to improve the anti-fouling and pure water flux performance of membranes. Antifouling performance and hydrophilicity of membranes were enhanced. Drug removal according to membrane surface charge by Donnan's exclusion mechanism. [ABSTRACT FROM AUTHOR]

Micelles of different types and properties are basically formed by the assembly of surfactants. The conditions for the formation of micelles, their shapes, sizes and morphologies are also different, and are discussed for surfactants, block copolymers and ionic liquids in the present article. Theories by Debye and others, Markov chain model, ladder model of micelle growth are employed to understand in detail the thermodynamics of micelles and mixed micelles formation. Apart from these, other concepts like effect of additives on micelle formation, application of polymeric, multicompartment micelles in drug delivery, fundamentals of formation of single and double critical micelle concentration and computer simulation methods for amphiphile aggregation are reviewed in the present study. [ABSTRACT FROM AUTHOR]

Acridinium esters, due to their capability for chemiluminescence (CL), are employed as indicators and labels in biomedical diagnostics and other fields. In this work, the influence of ionic surfactants, hexadecyltrimethylammonium chloride and bromide (CTAC and CTAB, cationic) and sodium dodecyl sulphate (SDS, anionic) on the CL parameters and mechanism of representative emitter, 10-methyl-9-[(2-methylphenoxy)carbonyl]acridinium trifluoromethanesulphonate (2MeX) in a H2O2/NaOH environment, is studied. Our investigations revealed that the type of surfactant and its form in solution have an impact on the CL kinetic constants and integral efficiencies, while changes in those emission properties resulting from the type of ion (Cl− vs. Br−) are negligible. The major changes were recorded for systems containing surfactants at concentrations higher than the critical micelle concentration. The cationic surfactants (CTAC, CTAB) cause a substantial increase in CL emission kinetics and a moderate increase in its integral efficiency. At the same time, the opposite effect is observed in the case of SDS. Molecular dynamics simulations suggest that changes in emission parameters are likely due to differences in the binding strength of 2MeX substrate with surfactant molecules, which is higher for SDS than for CTAC. The results can help in rational designing of optimal acridinium CL systems and demonstrate their usefulness in distinguishing the pre- and post-micellar environment and the charge of surfactants. [ABSTRACT FROM AUTHOR]

The genus Fictibacillus contains twelve species significant in the synthesis of cellulose-degrading enzymes and phenylalanine dehydrogenase, isolated mainly from marine sedimentary environments. Here, we report a new biosurfactant-producing strain, Fictibacillus nanhaiensis ME46, isolated from Daqing oil field in China. The biosurfactant extracted from Strain ME46 was determined as surfactin, one of the representative families of lipopeptide biosurfactants. The yield of the surfactin produced by strain ME46 was 0.62 g·L−1 as determined by high-performance liquid chromatography, and the critical micelle concentration (CMC) of the surfactin was estimated to be about 68 mg·L−1 and the surface tension at CMC was 35.1 mN·m−1. This study extended our knowledge about the role of the species Fictibacillus nanhaiensis in the ecosystem of natural environments such as the oil field. [ABSTRACT FROM AUTHOR]

Ionic detergents enable applications and cause harm in biospheres due to cell toxicity. The utility of covalent combinations between ionic and non‐ionic detergent headgroups in modulating cell toxicity remains speculative due to the yet rarely explored synthesis. We close this gap and establish the modular synthesis of ionic/non‐ionic hybrid detergents. We restructure a combinatorial methallyl dichloride one‐pot coupling into a two‐step coupling, which reduces by‐products, improves product yields, and enables the gram‐scale preparation of asymmetric, cationic/non‐ionic and anionic/non‐ionic hybrid detergents. Our modular synthesis delivers new modalities for the design of ionic detergents, including an unprecedented scaling of properties that determine applications, such as charge, critical micelle concentration, solubilizing properties, hard water tolerance, and cell compatibility. We uncover that shielding the charge in ionic headgroups can switch the detergent species that is toxic to cells from monomers to mixtures of monomers and micellar assemblies. Establishing the chemistry of ionic/non‐ionic hybrid detergents provides a missing evolutionary link in the structural comparison of ionic and non‐ionic detergents, enables an easy synthesis access to yet unexplored chemical spaces of asymmetric hybrid materials, and delivers new modalities for designing the toxicity of supramolecular nanomaterials. [ABSTRACT FROM AUTHOR]

Conventional perfluorooctane sulfonyl fluorosurfactants (PFOS) have caused great harm to human health and the environment, but the irreplaceable properties of fluorosurfactants offer great values. To this end, we have synthesized a highly surface active, environmentally friendly sulfonate surfactant (PBSA) with a perfluorinated branched short chain and systematically investigated its thermal stability, surface properties, wetting performance, and so forth. The minimal surface tension (γCMC) and critical micelle concentration (CMC) of the aqueous solution of PBSA were 22.70 mN/m and 0.067 mmol/L, respectively. In addition, the binary system of PBSA and cetyltrimethylammonium bromide (CTAB) exhibited excellent synergistic effects: γCMC and CMC values were reduced to 18.94 mN/m and 0.008 mmol/L. Moreover, the PBSA/CTAB mixed solution exhibited superb wetting ability: it could achieve complete wetting of PTFE plates at low concentrations (1.82 × 10−3 mol/L), with a minimum wetting concentration of only 2.84 × 10−5 mol/L. [ABSTRACT FROM AUTHOR]

Amino acid surfactants have mild performance and are sourced from renewable biomass. Compared to classical surfactants, Gemini surfactants have superior properties. The amino acid Gemini surfactants are believed to be adopted more widely. The Gemini surfactant with tripeptide structure, sodium di(lauroyl glutamyl) lysine (DLGL), was prepared by amidation utilizing methyl laurate, glutamate and lysine and characterized by 1H NMR, 13C NMR and MS. Additionally, the pKa value, surface activities, aggregation, foaming properties and emulsifying attributes of the DLGL surfactant in aqueous solution with varied pH values were examined. The results indicate that the protonation‐deprotonation behavior of the DLGL surfactant is highly dependent on pH values. The surface tension, critical micelle concentration (cmc), foamability and foam stability exhibited superior performance at pH 6 and 7. Conversely, superior emulsifying ability was observed at pH 9 and 10. Moreover, the spherical vesicles were formed by the DLGL surfactant at pH 6, 7 or 8 while the micelles were generated at pH 9 or 10. [ABSTRACT FROM AUTHOR]

Lipopeptides can self-assemble into diverse nanostructures which can be programmed to incorporate peptide sequences to achieve a remarkable range of bioactivities. Here, the influence of peptide sequence and chirality on micelle structure and interactions is investigated in a series of lipopeptides bearing two lysine or D-lysine residues and tyrosine or tryptophan residues, attached to a hexadecyl lipid chain. All molecules self-assemble into micelles above a critical micelle concentration (CMC). Small-angle x-ray scattering (SAXS) is used to probe micelle shape and structure from the form factor and to probe inter-micellar interactions via analysis of structure factor. The CMC is obtained consistently from surface tension and electrical conductivity measurements. We introduce a method to obtain the zeta potential from the SAXS structure factor which is in good agreement with directly measured values. Atomistic molecular dynamics simulations provide insights into molecular packing and conformation within the lipopeptide micelles which constitute model self-assembling colloidal systems and biomaterials. Lipopeptides show great potential as green surfactants but the aggregation behavior of designed lipopeptides bearing linear peptide sequences remains understudied. Here, the authors examine the micellization of chiral lipopeptides bearing lysine-rich tripeptide sequences and investigate structural effects as well as the surface tension and electrical conductivity. [ABSTRACT FROM AUTHOR]

A spectrophotometric method has been employed to study micellization of nonionic surfactants (NSs), namely, polyoxyethylated alkylphenols, Triton X-100 (TX-100) and Triton X-114 (TX-114), in aqueous solutions. The spectral characteristics have been calculated for the curves of light absorption by surfactant solutions in concentration ranges of 0.02–0.80 and 0.02–0.40 mmol/L for TX-100 and TX-114, respectively. The influence of the steps of scanning along the wavelength scale (0.1, 0.2, 0.5, and 1.0 nm) on the positions of the maxima and the intensities of the absorption has been studied. The optical density has been found to increase monotonically throughout the concentration range. It has been revealed that, at all scanning steps, a bathochromic shift is observed for the absorption maximum of the long-wavelength band (275 nm) by 1.5 and 2.0 nm for TX-114 and TX-100, respectively, at certain NS concentrations. The curve for the dependence of absorption maximum position on NS concentration exhibits a characteristic inflection, whose position depends on the scanning step. A new method has been proposed for the spectrophotometric determination of the critical micelle concentrations (CMCs) of TX-100 and TX-114 from the dependence of the position of the absorption maximum of the long-wavelength band in the electronic absorption spectrum on the surfactant concentration in an aqueous solution. It has been found that a scanning step of 0.1 nm is optimal for the graphical determination of CMC. The CMC values have been determined for TX-100 and TX-114. The obtained values have appeared to be consistent with the literature data and equal to (0.24 ± 0.02) and (0.20 ± 0.01) mmol/L, respectively. [ABSTRACT FROM AUTHOR]

Garlic suffers from frequent pathogenic diseases, seriously affecting its yield and quality. Biosurfactants have been reported with high antimicrobial activity and wide antimicrobial spectrum. Biosurfactant-producing bacteria existing in garlic farmland soil are expected to be used in control of garlic diseases. In this study, strain FA1 having high yield of biosurfactants was isolated from garlic farmland soil. Combined with morphological analysis and its 16S rDNA sequences analysis, the strain FA1 was identified as Pseudomonas aeruginosa. HPLC-MS analysis showed that biosurfactants produced from P. aeruginosa FA1 were presented rhamnolipids, mainly Rha-C8-C10, Rha-Rha-C8-C10, Rha-C10-C10 and Rha-Rha-C10-C10. The proportion of mono-rhamnolipids and di-rhamnolipids was about 1 : 1. P. aeruginosa FA1 can produce 7.96 g/L of rhamnolipids. The FA1 rhamnolipids can decrease the air-water surface tension to 27.5 mN/m with a critical micelle concentration of 50 mg/L. Through the agar diffusion method, P. aeruginosa FA1 exhibited high antimicrobial activity with diameters of inhibition zones larger than 20 mm to both the garlic potential pathogenic bacteria and fungi. Rhamnolipids produced from P. aeruginosa FA1 induced the potential pathogens to generate higher level of intracellular Reactive Oxygen Species (ROS), thus, exerting antimicrobial effects. P. aeruginosa FA1 can highly produce rhamnolipids biosurfactants and exhibit high antimicrobial effect to the garlic potential pathogens. This study verified that indigenous biosurfactant-producing bacteria from garlic farmland soil were feasible and effective to control garlic potential pathogens. [ABSTRACT FROM AUTHOR]

To achieve the optimal alginate-based oral formulation for delivery of hydrophobic drugs, on the basis of previous research, we further optimized the synthesis process parameters of alginate-g-oleylamine derivatives (Ugi-FOlT) and explored the effects of different degrees of substitution (DSs) on the molecular self-assembly properties of Ugi-FOlT, as well as the in vitro cytotoxicity and drug release behavior of Ugi-FOlT. The resultant Ugi-FOlT exhibited good amphiphilic properties with the critical micelle concentration (CMC) ranging from 0.043 mg/mL to 0.091 mg/mL, which decreased with the increase in the DS of Ugi-FOlT. Furthermore, Ugi-FOlT was able to self-assemble into spherical micellar aggregates in aqueous solution, whose sizes and zeta potentials with various DSs measured by dynamic light scattering (DLS) were in the range of 653 ± 25~710 ± 40 nm and −58.2 ± 1.92~−48.9 ± 2.86 mV, respectively. In addition, RAW 264.7 macrophages were used for MTT assay to evaluate the in vitro cytotoxicity of Ugi-FOlT in the range of 100~500 μg/mL, and the results indicated good cytocompatibility for Ugi-FOlT. Ugi-FOlT micellar aggregates with favorable stability also showed a certain sustained and pH-responsive release behavior for the hydrophobic drug ibuprofen (IBU). Meanwhile, it is feasible to control the drug release rate by regulating the DS of Ugi-FOlT. The influence of different DSs on the properties of Ugi-FOlT is helpful to fully understand the relationship between the micromolecular structure of Ugi-FOlT and its macroscopic properties. [ABSTRACT FROM AUTHOR]

Liamocins, a group of high-density glycolipids, are only produced by certain strains of the yeast-like fungi in the genus Aureobasidium. Until now, few studies have focused on the surfactant properties of liamocins produced from the highly diverse tropical strains of Aureobasidium. Therefore, the aims of this research were to screen the liamocin production from tropical strains of Aureobasidium spp. and to characterize their surfactant properties. A total of 41 strains of Thai Aureobasidium spp. were screened for their ability to produce liamocins, and the products were detected using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and thin-layer chromatography. Of those strains, 30 strains of Aureobasidium spp. tested were found to produce liamocins with yields ranging from 0.53 to 10.60 g/l. The nature of all crude liamocins was heterogeneous, with different compositions and ratios depending on the yeast strain. These liamocins exhibited relatively high emulsifying activity against vegetable oils tested, with an emulsification index of around 40–50%; the emulsion stability of some liamocins was up to 30 days. The obtained critical micelle concentration values were varied, with those ​​of liamocins produced from A. pullulans, A. melanogenum and A. thailandense falling in ranges from 7.70 to 119.78, 10.73 to > 1,000, and 68.56 to > 1,000 mg/l, respectively. The emulsification activity of liamocins was higher than that of the analytical grade rhamnolipids. These compounds showed strong surface tension reduction in a sodium chloride concentration range of 2–12% (w/v), pH values between 3 and 7, and temperatures between 4 and 121 °C. This is the first report of liamocins produced by A. thailandense. [ABSTRACT FROM AUTHOR]

Plant-derived biosurfactants are widely used due to their emulsifying and surface-active properties and can be applied in various products. The aim of this present study was to develop a mouthwash using chitosan hydrochloride and saponins extracted from the plants Chenopodium quinoa and Glycine max. After extraction of the biosurfactants using the Soxhlet method, they were characterized with the aid of infrared spectroscopy and subjected to determination of critical micelle concentration, which was found to be 4.0 and 3.5 g/L for C. quinoa and G. max, respectively. The stability of the emulsions was investigated in the presence of different oils and at different values of temperature, pH, and salinity, which showed an emulsification index greater than 40% under all conditions analyzed. After obtaining the mouthwash formulation, tests of foaming capacity, pH, and genotoxicity were performed in cells of onion (Allium cepa) roots. No presence of micronuclei was found in the roots exposed to the formulation, which indicates that there was no aggression to the cells. The results of antimicrobial susceptibility tests revealed bacteriostatic/bactericidal activity as well as antibiofilm activity of formulations against the microorganisms tested. In conclusion, the biosurfactants present in extracts from C. quinoa and G. max were found to be stable, non-toxic molecules with antimicrobial activity, with potential to replace toxic emulsifying agents commonly used in commercial products. [ABSTRACT FROM AUTHOR]

Present study determines the Critical Micelle Concentration (CMC) of some market available detergents at different temperatures in aqueous solutions. For this study we use Sunlight Surf and Safed Surf. Sodium Acetate Electrolyte was used. Conductance data was taken at different temperatures (15°C, 25°C, 35°C). From this study it was observed that with increase in temperature, cmc value decreases. Addition of electrolyte with surfactants (detergent), decrease cmc value which support our basic concept of surface chemistry. Different thermodynamic parameters like, ΔG, ΔH, ΔS were calculated and also supporting the formation of cmc. [ABSTRACT FROM AUTHOR]

Amphiphilic helical polycarbodiimides bearing side chains with terminal alkyne groups provide a unique platform for construction of polymeric micelles. Incorporation of propargyl pendants into polyguanidine backbone allowed post‐polymerization modification with azide terminated, random coil, poly(N‐isopropylacrylamide), PNIPAM15K and poly(ethyleneglycol), PEG2K moieties using copper‐catalyzed click reaction (CuAAC). Thus, four new amphiphilic brush copolymers with varying grafting density were synthesized and their self‐assembly behavior in aqueous medium was studied by combination of TEM, SEM, AFM, and optical microscopy techniques. It was shown the formation of micellar structures at critical micelle concentration (CMC) ranging from 1.58 × 10−5 to 1.05 × 10−3mg mL−1. A hydrophobic drug doxorubicin (DOX) was then encapsulated successfully into these micellar structures with encapsulation efficiency (EE) falling in the range from 16% to 27%. Further, the cellular uptake studies were carried out by using HeLa cells and the cytotoxic activity of DOX‐loaded micelles was determined to be less than 65% of cell viability at a concentration of 0.250 mg mL−1. Fluorescence microscopy imaging revealed importing the micelles into the cells by endocytosis and internalization of the DOX into nucleus of the HeLa cells. [ABSTRACT FROM AUTHOR]

Significant research has been conducted to minimise environmental impacts and promote the sustainable use of resources and raw materials. Microbial surfactants are an example of advanced materials obtained from sustainable production processes. In the present study, a biosurfactant was produced by the yeast Starmerella bombicola ATCC 22214 grown in a previously selected low-cost mineral medium containing 10% sucrose, 1.2% canola oil, and 0.5% corn steep liquor. The biosurfactant reduced surface tension from 72 ± 0.1 to 32.76 ± 0.3 mN/m. The yield was 23 g/L, and the critical micelle concentration was 0.6 g/L. The biosurfactant emulsified 96.25 ± 0.08% of used motor oil, was characterised as a sophorolipid, and exhibited stability under extreme conditions with no significant loss of its properties. Toxicity was assessed by exposing the microcrustacean Artemia salina and the zebrafish (Danio rerio) to the biosurfactant. The biosurfactant proved efficient for use in remediation processes, removing 97.8% and 69.2% of the petroleum derivative from sand in kinetic and static tests, respectively, and removed 91.5% of the contaminant from seawater. The results indicate the potential of this new biosurfactant for the mobilisation and solubilisation of hydrocarbons in the marine environment. This green biomolecule is a promising technology for the replacement of chemical dispersants in the remediation of aquatic and soil systems. [ABSTRACT FROM AUTHOR]

This work describes the production of a novel biosurfactant produced by the bacterium Bacillus invictae UCP1617 cultivated using an alternative substrate and its use in the formulation of an eco‐friendly detergent. A factorial design was used to optimize agitation, temperature, and inoculum size in a mineral medium containing 1.5% corn steep liquor in 100‐mL shake flasks. The best conditions (175 rpm, 28°C, and 4% inoculum) were used to scale up biosurfactant production in a 50‐L bioreactor. Surface tension of the fermentation medium decreased from 69.5 to 30.2 mN/m within 72 h. The biosurfactant exhibited a critical micelle concentration (CMC) of 0.900 ± 0.08 g/L. The biosurfactant formed stable oil‐in‐water emulsions of motor oil and petroleum, achieving emulsification indices of 90.80% and 99.00%, respectively. An eco‐friendly detergent was formed that included biosurfactant at several different concentrations, 0.2 (wt) % hydroxyethyl cellulose and 0.2% potassium sorbate. The detergent remained stable under extreme conditions of pH, temperature, and salinity when stored for 90 days. The detergent was nontoxic to cabbage, cherry tomato plants, and the microcrustacean Artemia salina. A detergent formulation containing biosurfactant at the CMC completely dispersed motor oil in seawater at a 1:1 surfactant/oil (vol/vol) ratio and removed 99.21% of motor oil (20 mL) contained in 60 g of clayey soil. The detergent removed 98.42% of the oil adhered to a glass surface and removed 75.00% of motor oil adsorbed to a porous surface. The application of this biosurfactant as an environmentally friendly additive for remediation processes is feasible. [ABSTRACT FROM AUTHOR]

This study investigates the temperature‐dependent micellization behaviors of saponin and sodium dodecyl sulfate (SDS) surfactants, which are both important for chemical enhanced oil recovery (CEOR). It also evaluates the effect of silica nanoparticles (SiO2) on these behaviors, given the growing interest in nanoparticle‐enhanced surfactants. The research focuses on the tunable properties of nanoparticle‐surfactant combinations. The structural differences between saponin and SDS were identified using FT‐IR and H‐NMR. The Du Noüy ring method was used to measure surface tension at various concentrations and temperatures (25–75 °C). FTIR analysis showed distinct differences between SDS and Saponin, associated with head group where there is hydroxyl groups in SDS solution. H‐NMR showed higher complexity of Saponin's structure, evidenced by its diverse sugar‐related proton peaks. Both SDS and Saponin reduce surface tension with temperature; SDS is more effective, lowering it to 42.1 mN/m versus 48.5 mN/m for Saponin. With SiO2, tensions drop to 39.2 mN/m for SDS and 45.5 mN/m for Saponin. Both surfactants maintain CMCs under reservoir temperature in the 0.05–0.1 wt % range. Saponin exhibited a more negative ΔG° and consistently negative ΔH°, indicating a thermodynamically favorable exothermic reaction. The novelty of this study lies in its focus on both anionic and nonionic surfactants under simulated reservoir conditions. The study focuses on the role of nanoparticles in enhancing surfactant stability and efficiency by addressing thermodynamic parameters. [ABSTRACT FROM AUTHOR]

Rhamnolipids, simply divided into mono‐rhamnolipids and di‐rhamnolipids, their physicochemical properties are structure‐dependent. This study explored to increase the proportion of di‐rhamnolipids biosynthesized from Pseudomonas aeruginosa and evaluate the relationship between activity and di‐rhamnolipids proportions. P. aeruginosa SGrhlC was constructed by increasing the rhlC gene in P. aeruginosa SG. HPLC‐MS results indicated that SGrhlC produced more di‐rhamnolipids (62.32%) than that of the wild‐type strain SG (45.24%). Both the species and proportion of di‐rhamnolipids were increased, mainly Rha‐Rha‐C8‐C10 and Rha‐Rha‐C10‐C10. The rhamnolipids produced by SGrhlC was thermostable and salt‐tolerant. The SGrhlC rhamnolipids decreased surface tension of water to 27.0 mN/m with a critical micelle concentration (CMC) of 50 mg/L and emulsified crude oil with an emulsification index of 66.9 ± 1.5%. The SGrhlC rhamnolipids exhibited antimicrobial activity against Staphylococcus aureus and Cladosporium sp. with IC50 (half maximal inhibitory concentration) values less than 15 mg/L, and washed 73.02% ± 1.77% of oil from petroleum‐contaminated soil. Physicochemical activities of three bacterial rhamnolipids varied with their di‐rhamnolipids proportions. Results indicated that the higher proportions of di‐rhamnolipids were, the lower CMC, better surface activity and higher washing oil rate were, while the weaker emulsifying activity and lower antimicrobial activity were. The SGrhlC rhamnolipids showed better surface activity and a lower critical micelle concentration, which was superior for wetting, foaming, desorbing and dispersing. This study revealed that P. aeruginosa can be genetically regulated to biosynthesize rhamnolipids with specific structure. Perspectives of the customized biosynthesis and applications of rhamnolipids were also discussed. [ABSTRACT FROM AUTHOR]

An amphiphilic three‐armed star polymer was synthesized through the polar cycloaddition reaction of a polyethylene glycol‐based macro‐triazide with an Yne‐terminated polycaprolactone in a molar ratio of 1:3 (click chemistry). Thus, each arm is itself a di‐block copolymer branched from the core, which is a 1,3,5‐triazine ring. The attachment of the pre‐synthesized hydrophobic segments to the hydrophilic segments in each arm leads to the creation of a 1,2,3‐triazole ring in the structure. Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (H‐NMR) spectroscopies were used to verify the structures. The micellization process of the prepared amphiphilic polymer was investigated in aqueous medium. For this purpose, the critical micelle concentration (CMC) was specified by the fluorometric method. Using the transmission electron microscopy (TEM) technique, it was observed that spherical self‐assemblies with a mean diameter of <100 nm are formed from the aggregation of the amphiphilic macromolecules. In addition, the hydrodynamic diameter (D¯H) of the polymeric micelles and their size distribution were examined by dynamic light scattering (DLS) technique. [ABSTRACT FROM AUTHOR]