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[Display omitted] Cationic surfactants have a wide range of applications, often associated with their affinity for a range of solid surfaces and their anti-microbial properties. Manipulating their adsorption and self-assembly properties is key to most applications, and this is commonly achieved through surfactant mixtures or manipulating their headgroup or alkyl chain structure. Achieving this through adjustments to their headgroup structure is less common in cationic surfactants than in anionic surfactants. Ethoxylation provides the ability to adjust the hydrophilic / hydrophobic balance, as extensively demonstrated in a range of anionic surfactants. This same approach has been applied here to a range of ethoxylated cationic surfactants in the form of the quaternary ammonium salts, and their tertiary nonionic equivalents before quaternisation. Their adsorption and self-assembly properties are investigated using predominantly the neutron scattering techniques of neutron reflectivity, NR, and small angle neutron scattering, SANS. The trends in the adsorption at the air–water interface and the self-assembly in aqueous solution demonstrate how the hydrophilic / hydrophobic balance can be adjusted by varying the degree of ethoxylation and the alkyl chain length, and illustrate the degree of interdependence of the different structural changes. The variation in the adsorption and the micelle structure shows how the surfactant conformation / packing changes as the degree of ethoxylation and alkyl chain length increases and how the introduction of charge induces further changes. [ABSTRACT FROM AUTHOR]

Current natural sources of mid‐cut alcohol (MCA), a key ingredient in cleaning formulations, present several challenges. One solution is to use insect oils instead of palm kernel oil (PKO) or coconut oil (CNO). In particular, black soldier fly (BSF) larvae oil is a promising raw material that provides a sustainable, natural feedstock for MCA. The estimation of its PCF leads to strongly negative values, driven by a very low land use change. The fact that low‐value by‐products are upgraded by BSF larvae is an additional advantage and avoids any competition with food crops. This study shows that BSF larvae oil can be a drop‐in replacement for PKO and CNO, leading to more sustainable ingredients for cleaning formulations. The technical proof of principle for the production of fatty alcohols has been demonstrated and up‐scaling to large commercial volumes should be straightforward. A potential barrier to consumer acceptance is expected to be lowered in the future. In certain regions or applications, successful market entry may already be possible today. [ABSTRACT FROM AUTHOR]

Increased demand and sustainability concerns for palm derivatives, which include the major plant‐based feedstocks for surfactants in household, personal care, and industrial & institutional (I&I) applications, is anticipated to cause supply concerns over the next decade. This article reviews the impact of the fatty acid alkyl chain length and unsaturation and resulting physical properties from non‐palm feedstocks on formulation, processing, and functionality. Potential adjustments and their limitations are also discussed. [ABSTRACT FROM AUTHOR]

Sulfur is a key element in most anionic surfactants. About 75% of sulfur currently is generated as a waste byproduct of petroleum refining, while most of the remainder is generated as a waste byproduct of natural gas refining. Assuming the world's fossil fuel use decreases in the future, what will happen with sulfur‐containing surfactants? Three possible alternatives are explored. First, alternate sources of sulfur could replace sulfur from fossil fuel. Second, surfactants that do not contain sulfur could replace those that contain sulfur. Third, other industries could replace sulfur in their products, while sulfur remains in surfactants. Each of these will be considered, and predictions will be made in terms of the likeliest outcomes. [ABSTRACT FROM AUTHOR]

In the endeavor to mimic natural light‐harvesting systems (LHSs), a persistent challenge has been the tendency of synthetic materials to adopt spherical architectures rather than the desired multitubular structures found in nature. In this study, a novel carboxylbetaine‐type zwitterionic surfactant with aggregation‐induced emission (AIE) properties is designed. By coassembling with anionic surfactants, multiwalled tubules comprising bilayer membranes ≈5 nm thick are successfully constructed. With AIE fluorophores densely packed at the center, their AIE properties are triggered to serve as an efficient antenna for light harvesting and energy transfer. This facilitated high antenna effects via energy transfer from cyan fluorescent donor to yellow fluorescent acceptor and then to red fluorescent acceptor. Additionally, the emission color can be adjusted from blue to red by manipulating the donor/acceptor/acceptor ratio, with pure white‐light emission achievable at specific ratios. This achievement not only realizes the construction of efficient sequential LHSs but also offers inspiration for the future design of artificial multitubular systems. [ABSTRACT FROM AUTHOR]

Sodium alkylbenzene sulfonates (ABS), or linear alkylbenzene sulfonates (LAS), are among the most common synthetic anionic surfactants and water pollutants, capable of causing both acute and chronic toxic effects on aquatic organisms. The selective determination of sodium alkylbenzene sulfonates as a distinct class of anionic surfactants in complex natural matrices is feasible by gas chromatography with mass spectrometric detection (GC–MS) in the form of linear alkylbenzenesulfonic acid methyl esters (LABSA ME). The behavior of LAS and LABSA ME was studied under ascending high-performance thin-layer chromatography (HPTLC) using Kieselgel 60 F254 and Sorbfil plates to purify extracts and preconcentrate analytes. A mixture of n-hexane with methanol (23 : 1, v/v) is proposed as a mobile phase. Under these conditions, sodium alkylbenzene sulfonates remain at the start line, while their derivatives (LABSA ME), obtained by methylation with trimethyl orthoformate in the presence of trifluoroacetic acid (yield η = 98%), form zones characterized by retention factors Rf of 0.62–0.71 on Kieselgel 60 F254 and Sorbfil plates, respectively. The repeatability of Rf values is characterized by a relative standard deviation of 6.1 and 5.9%, respectively (n = 16). The completeness of the extraction (95.0–100.0%) of analytes from the plates is noted using descending HPTLC with acetonitrile. The applicability of the HPTLC method for preconcentrating analytes and purifying extracts is demonstrated using real water samples. Using GC–MS with electron impact ionization, concentrations of sodium alkylbenzene sulfonates were found in water sampled from the southern basin of Lake Baikal at a depth of 400 m (0.24 ± 0.02 µg/L) and in water obtained from melting snow collected from the ice of the Krestovka River at its mouth near the settlement of Listvyanka (31.1 ± 1.0 µg/L). [ABSTRACT FROM AUTHOR]

This study investigates the occurrence and distribution of chemical pollutants, including total petroleum hydrocarbons (TPHs), organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), anionic surfactants, and total organic carbon (TOC), in the Marine Protected Areas (MPAs) waters in the northern Persian Gulf. Water samples were collected from five MPAs during the winter and summer of 2022. The study identified significant seasonal variations, with higher pollutant levels recorded in winter compared to summer. Concentrations of ∑19PCBs (ng/L), anionic surfactants (µg/L), TPHs (mg/L), and TOC (mg/L) ranged from 0.72 to 4.66, 10 to 79, ND to 134.63, and 0.5 to 114.58 in winter, and from 2.49 to 5.05, 11 to 30, ND to 20.26, and 0.15 to 5.27 in summer, respectively. The pollution patterns revealed the Mond protected area as a major pollution hotspot, compromising its ecological health. The results highlight the critical need for targeted pollution control and enhanced conservation measures in the region's MPAs to protect biodiversity and marine ecosystems. [ABSTRACT FROM AUTHOR]

Oxidative stress of Lake Baikal organisms can be caused by pollution of nearshore with anionic surfactants or heavy metals. Some specific heavy metals are essential for aquatic organisms. At present, there are no data concerning heavy metal content caused by anthropogenic pollution or chemotaxonomic features of Baikal sponges. Here, we consider the applicability of total reflection x‐ray fluorescence (TXRF) to analyze heavy metals in Lubomirskia baikalensis to fill this gap. It was shown that TXRF method can be successfully applied to the fast and reliable quantification of Cu, Zn, Fe, and Mn in this object. Evaluation of different sample treatment procedures showed that the acid digestion by HNO3/H2O2 mixture is an optimal procedure for the preparation of sponges compared with suspension preparation. It helps to improve sensitivity, eliminate the effects of particle size and specimen heterogeneity. The total uncertainty of the TXRF results associated with the sample preparation, taking, depositing, and measuring of the specimen was 6%–18% for Mn, 3%–5% for Cu, 5%–12% for Fe, and 4%–5% for Zn. To validate the developed method, the TXRF results were compared with the data obtained by wavelength dispersive x‐ray fluorescence spectrometry. A good agreement of results was achieved. TXRF data show the dominance of essential heavy metals in L. baikalensis (n = 14) among other heavy metals. Correlations between Cu/Zn contents (R2 = 0.515) as well as between Fe/Mn contents (R2 = 0.972) can be explained by the contribution of them to L. baikalensis antioxidant system. [ABSTRACT FROM AUTHOR]

In this work, magnesia‐alumina spinel foam ceramics were prepared by foaming‐sol method using magnesia alumina spinel as raw material, anionic surfactant potassium oleate (PO) as foaming agent, and alumina sol as curing agent. The curing mechanism and the effect of alumina sol content on the stability of foam slurry and the properties of foam ceramics were investigated. In the foam slurry, the alumina sol can react with PO, so magnesia‐alumina spinel can be fixed in the foam structure through the gel network to improve the stability of the foam slurry. The gelation process reduces the viscosity of the foam slurry. The pores of magnesia‐alumina spinel foam ceramics sintered at 1500°C are mostly closed pores and the average pore was 29.7–42.1 µm. With the increase of alumina sol content, the bulk density of magnesia‐alumina spinel foam ceramics increased from 1.3 to 1.9 g/cm3, the cold compressive strength from 8.8 to 22.7 MPa, and the thermal conductivity from.417 to.806 W·m−1·K−1(350°C). [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]

Incorporating CO2-philic functionalities into surfactant structure is proposed to address the drawbacks of conventional foaming agents such as premature rupture of lamellae in contact with oil, surfactant loss due to adsorption on rock or partitioning between oil and water, and salinity and temperature tolerance issues. Increased activity at the gas/water interface and less surfactant adsorption to the rock due to the presence of CO2-philic chains results in higher foam durability in the presence of oil. In the present paper, a comprehensive study on the adsorption of anionic CO2-philic surfactants onto sandstone rock surface is performed to understand adsorption mechanisms through the addition of CO2-philic tail groups in surfactant structure by observing the changes in concentration, static adsorption, and point of zero charge measurements. The static adsorption tests, Fourier Transform Infrared, and the X-ray Photoelectron Spectroscopy techniques were employed to investigate the interaction of surfactants with crushed Berea sandstone core sample at 90 °C. The static adsorption values of the S (single-tail), D (double-tail), and T (triple-tail) anionic surfactants were reported to be 0.53, 0.40, and 0.6 mg /g, respectively. The effect of alkali on the adsorption process of surfactants was also investigated and the adsorption of synthesized surfactants was found significantly low in alkaline conditions. A variety of analyses, including model fitting along with kinetics and thermodynamics studies at 30, 40, and 50 °C were performed to predict the adsorption behavior. The adsorption isotherm was found to best fit in Langmuir model. The process showed the best fit in the pseudo-second-order reaction kinetics model. The spontaneity of the adsorption process was verified by thermodynamic feasibility studies of the process. [ABSTRACT FROM AUTHOR]

The present work aimed to evaluate whether the use of an innovative method such as hydrodynamic cavitation (HC) is suitable for the simultaneous removal of surfactants of different chemical natures (non-ionic, anionic and cationic) from actual car wash wastewater at different numbers of passes through the cavitation zone and different inlet pressures. An additional novelty was the use of multi-criteria decision support, which enabled the selection of optimal HC conditions that maximized the removal of each group of surfactants and chemical oxygen demand (COD) with minimal energy input. For the optimal HC variants, Fourier transform infrared spectroscopy (FT-IR/ATR) as well as investigations of surface tension, zeta potential, specific conductivity, system viscosity and particle size were carried out. The highest reduction of non-ionic surfactants was found at 5 bar inlet pressure and reached 35.5% after 120 min. The most favourable inlet pressure for the removal of anionic surfactants was 3 bar and the removal efficiency was 77.2% after 120 min, whereas the most favourable inlet pressure for cationic surfactant removal was 3 bar, with the highest removal of 20% after 120 min. The obtained results clearly demonstrate that HC may constitute an effective, fast and cost-efficient method for removing surfactants from real industrial wastewater. [ABSTRACT FROM AUTHOR]

The chemical enhanced oil recovery (cEOR) uses substances to improve the mobility of petroleum in reservoirs. Among these substances are the surfactants, whose purpose is to change the wettability and interfacial tension (IFT). We focus on experiments of surfactants in rocks from Chicontepec Paleochannel. CTAB, DTAB and SDS surfactants in brines of NaCl and KCl and mineral oil were investigated for reduction of IFT and contact angle alteration. The sessile and pendant drop methods were used to determine the IFT. The electrical affinity of the rock surface, dissolved ions, and the surfactant molecules, play key roles in the alteration of wettability and IFT. Thus, one scheme of interactions between the electrical charges is proposed on the basis of the rocky characterization and the following results: the lowest contact angle was 106° with CTAB at 0.01 wt% in brines at 9.25 g/L NaCl, and 108° with SDS at 0.01 wt% in brines at 20 g/L NaCl. The smallest IFT was 0.813 dyn/cm with CTAB at 0.5 wt% in brines at 5 g/L KCl. This work serves as first assessments of these surfactants to enhance the production in Chicontepec, employing cheap tensoactives to increase the applicability. Besides, these results will guide future displacement tests as cEOR lab simulation. [ABSTRACT FROM AUTHOR]

[Display omitted] Nonionic surfactants can counter the deleterious effect that anionic surfactants have on proteins, where the folded states are retrieved from a previously unfolded state. However, further studies are required to refine our understanding of the underlying mechanism of the refolding process. While interactions between nonionic surfactants and tightly folded proteins are not anticipated, we hypothesized that intermediate stages of surfactant-induced unfolding could define new interaction mechanisms by which nonionic surfactants can further alter protein conformation. In this work, the behavior of three model proteins (human growth hormone, bovine serum albumin, and β-lactoglobulin) was investigated in the presence of the anionic surfactant sodium dodecylsulfate, the nonionic surfactant β-dodecylmaltoside, and mixtures of both surfactants. The transitions occurring to the proteins were determined using intrinsic fluorescence spectroscopy and far-UV circular dichroism. Based on these results, we developed a detailed interaction model for human growth hormone. Using nuclear magnetic resonance and contrast-variation small-angle neutron scattering, we studied the amino acid environment and the conformational state of the protein. The results demonstrate the key role of surfactant cooperation in defining the conformational state of the proteins, which can shift away or toward the folded state depending on the nonionic-to-ionic surfactant ratio. Dodecylmaltoside, initially a non-interacting surfactant, can unexpectedly associate with sodium dodecylsulfate-unfolded proteins to further impact their conformation at low nonionic-to-ionic surfactant ratio. When this ratio increases, the protein begins to retrieve the folded state. However, the native conformation cannot be fully recovered due to remnant surfactant molecules still adsorbed to the protein. This study demonstrates that the conformational landscape of the protein depends on a delicate interplay between the surfactants, ultimately controlled by the ratio between them, resulting in unpredictable changes in the protein conformation. [ABSTRACT FROM AUTHOR]

This research investigates the impact of gamma irradiation on epoxy-MWCNT nanocomposites for satellite deployment mechanisms. Nanocomposites, enhanced with surfactants, were meticulously prepared and subjected to controlled gamma irradiation (250–1000 kGy) utilizing the Cobalt-60 facility Industrial Mega Gamma-1 at NCRRT in Egypt. Surface tension measurements explored surfactant effects on epoxy-MWCNT composites in acetone. Acetone reduced tension from 26.7 to be 24.2 (mN/m). Surfactants (Tween 80, SDS) effectively lowered tension (24.4 mN/m), while surfactant-free systems had higher tension (25.1 mN/m). Cationic surfactant (CTAB) slightly increased tension (25.4 mN/m) but aided MWCNT dispersion. Nonionic and anionic surfactants showed superior dispersing power, aligning with MWCNTs and enhancing dispersion. Thermogravimetric analysis (TGA) unveiled alterations in the thermal stability of epoxy-MWCNT nanocomposites induced by radiation, particularly evident at elevated doses (500 and 1000 kGy). Notably, surfactant-modified specimens exhibited discernible effects on various thermal stability parameters. DMA analysis revealed radiation-induced changes in viscoelastic properties. Unirradiated epoxy exhibited a Tg of 58 °C, while 250 kGy irradiation enhanced crosslinking (Tg: 64 °C). Higher doses (500 kGy, 1000 kGy) caused marginal Tg changes. Surfactant-modified samples showed varied effects, with Tween 80 emphasizing its role in phase separation. Results highlighted radiation's influence on stiffness and energy dissipation. Shape memory behavior indicated increased recovery time with higher doses, except at 250 kGy. Epoxy-MWCNT exhibited a stable recovery time, suggesting a MWCNT stabilizing effect. Fixation rates consistently reached 100%, indicating improved shape recovery influenced by MWCNTs and surfactants. This study provides insights into optimizing nanocomposites for satellite deployment applications. [ABSTRACT FROM AUTHOR]

Ordered macroporous silica particles as a photomaterial transparent solid matrix were synthesized from sodium silicate (Na2SiO3) as a silica source and sodium lauryl sulfate (SLS, an anionic surfactant), as a template to form pores via the consecutive sol–gel spray drying. The investigation is carried out in two stages, (1) controlling the particle morphology to obtain a spherical shape and (2) controlling the pore structure. The concentrations of the SiO2 precursor, carrier gas flow rate, feeding rate, and drying temperature were varied to identify their effects on particle morphology. Spherical and donut-shaped particle morphologies are more prominent when these parameters are used. On the other hand, the addition of SLS to the SiO2 precursor resulted in controlled macroporous silica particles, depending on the SLS concentration. The deposition of ZnO quantum dots (QDs) on the silica surface stabilizes the optical properties of ZnO by increasing the intensity of photoluminescence (PL) emission and demonstrating excitation-wavelength-dependent photoluminescence. The ZnO/SiO2 composite particles demonstrated the highest PL intensity with the use of 1 CMC SLS addition and a ZnO concentration of 25% mol, which was almost 30,000 times greater than that of pure ZnO particles. Therefore, an even distribution of ZnO QDs on the silica surface, which is influenced by the silica morphology and its ZnO concentration ratio, can minimize ZnO QDs agglomeration, directly reducing its functional characteristics as a photomaterial. [ABSTRACT FROM AUTHOR]

In this study, water‐based pressure‐sensitive adhesives (PSAs) were synthesized through an emulsion polymerization process using n‐butyl acrylate, methacrylic acid, acrylic acid, and N‐vinylpyrrolidone monomers, in combination with anionic and non‐ionic surfactants. The PSA was coated onto the corona‐treated surface of a BOPP film using a Mayer bar to prepare packaging tape. The effect of surfactant concentration on the properties of the resulting copolymer and PSA was investigated. The chemical structure, component distribution, and thermal behavior of the copolymer were analyzed using FTIR, HPLC, and DSC. The physical properties of the synthesized copolymer, such as solid content, viscosity, particle size, and gel content, were also determined. The performance of the prepared packaging tapes was evaluated through loop tack, 180° peel, and holding shear time tests. The results indicated that surfactant concentration significantly affected the adhesive's performance. Notably, the use of a 2.5 wt% surfactant mixture yielded promising results, with high monomer conversions and excellent adhesion properties in the tape. [ABSTRACT FROM AUTHOR]

To clarify the adsorption behavior of fluorocarbon surfactants on PMMA surfaces, the contact angles of two nonionic fluorocarbon surfactants (FNS-1 and FNS-2) and an anionic fluorocarbon surfactant (FAS) on polymethylmethacrylate (PMMA) surface were determined using the sessile drop method. Moreover, the effects of molecular structures on the surface tension, adhesion tension, solid–liquid interfacial tension, and adhesion work of the three fluorocarbon surfactants were investigated. The results demonstrate that the adsorption amounts for three fluorocarbon surfactants at the air–water interface are 4~5 times higher than those at the PMMA–solution interface. The three fluorocarbon surfactants adsorb on the PMMA surface by polar groups before CMC and by hydrophobic chains after CMC. Before CMC, FNS-2 with the smallest molecular size owns the highest adsorption amount, while FAS with large-branched chains and electrostatic repulsion has the smallest adsorption amount. After CMC, the three fluorocarbon surfactants form aggregates at the PMMA-liquid interface. FAS possesses the smallest adsorption amount after CMC. Besides, FNS-1 possesses a higher adsorption amount than FNS-2 due to the longer fluorocarbon chain and the lower CMC value of FNS-1. The adsorption behaviors of nonionic and anionic fluorocarbon surfactants on the PMMA surface are different. FAS forms interfacial aggregates before CMC, which may be attributed to the electrostatic interaction between the anionic head of FAS and the PMMA surface. [ABSTRACT FROM AUTHOR]

Reversed-phase liquid chromatography (RPLC) relies on a non-polar stationary phase and a more polar hydro-organic mobile phase, where compound retention is primarily governed by hydrophobicity, with more hydrophobic compounds being retained longer. The introduction of secondary equilibria in the chromatographic system through additives, such as anionic surfactants and ionic liquids (ILs), was proposed to mitigate ionic interactions between positively charged analytes and the anionic free silanol groups in non-endcapped stationary phases, thereby preventing increased retention and peak tailing. Additionally, the combined hydrophobic and ionic interactions between cationic analytes and the ions in these additives was demonstrated to create mixed retention mechanisms that influence retention and selectivity. In this regard, this study investigates aqueous chromatographic systems incorporating both the anionic surfactant sodium dodecyl sulfate (SDS) and the IL 1-hexyl-3-methylimidazolium chloride as mobile phase reagents. This combination of reagents modulates the retention, eliminating the need for organic solvents and resulting in highly sustainable HPLC procedures. The chromatographic behavior was assessed using two different C18 columns (Zorbax Eclipse and XTerra-MS). The strength of solute interactions was estimated by calculating equilibrium parameters and the contributions of hydrophobic and ionic interactions through simple mathematical models. Focusing on the retention of six basic drugs (β-adrenoceptor antagonists), the study highlighted the significant role of ionic interactions. The results demonstrate the feasibility of using aqueous systems combining SDS and an IL for the efficient separation of moderately polar basic compounds without the use of organic solvents. [ABSTRACT FROM AUTHOR]

Linear alkyl benzene sulfonates (LASs) with alkyl chains from C10 to C14 are the most commonly used anionic surfactants in household laundry. However, LAS toxicity toward agricultural soil further could be formed at a risk for fruits and vegetables grown on the land, so that to develop a sensitive and precise analytical technique for determination of trace residual sulfonates in vegetables is very important for health. This study developed a QuEChERS extraction coupled to liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for analyzing LASs in vegetables and fruits. The best results were obtained using acetonitrile as the extraction solvent combined with 25 mg primary secondary amine and 25 mg graphitized carbon black as sorbents. The linearity ranged between 1 and 250 ng/mL as well as limit of quantification (LOQ) was obtained in the range of 0.01–0.23 ng/mL of the proposed analytical method. The proposed method was utilized to detect the real spinach samples and water spinach planted with LASs‐spiked water, and the results showed the trace LASs were detected with concentration between 1.8 and 29.1 ng/g. In this study, a thorough optimization and validation of different amount of sorbent cleanup efficiency approaches was performed for the first time for the analysis of LAS. [ABSTRACT FROM AUTHOR]

Tomato peel by-products contain high levels of lycopene, which has traditionally been extracted using organic solvents. This research focuses on the optimisation of a sustainable method to obtain a lycopene-rich extract using the biodegradable anionic surfactant sodium dodecyl sulphate (SDS). A Plackett–Burman experimental design was used to investigate the effect of seven factors on the extraction of carotenoids from tomato peels using sodium dodecyl sulphate (SDS volume and concentration, homogenisation intensity and time, sonication phase, extraction time and ultracentrifugation intensity). Based on the responses of total carotenoid extraction, the SDS volume, the use of ultrasound and the extraction time significantly influenced the extraction yield and were selected for optimisation using a Box–Wilson experimental design. The final green extraction protocol (1 g sample + 11.9 ml SDS 0.3%, homogenisation at 13,500 rpm for 2 min, ultrasound phase, agitation for 8.2 h and ultracentrifugation) was selected after quantification of total carotenoids by UV–VIS and HPLC-DAD. Finally, we used nuclear magnetic resonance to demonstrate a high lycopene purity in the carotenoid extract obtained. Furthermore, using transmission electron microscopy, we observed the presence of intact chromoplasts in the extract, protecting the carotenoids from the exposure to external agents. Thus, this work reports an optimised method for the sustainable extraction of carotenoids and demonstrates the viability of the degradable solvent SDS for the extraction of liposoluble bioactive compounds, like carotenoids and mainly lycopene. The lycopene extract could be used for the technological and nutritional enrichment of new foods and/or the design of nutraceuticals. [ABSTRACT FROM AUTHOR]

We investigated the potential ecological risks and harm to aquatic organisms posed by anionic surfactants such as α-olefin sulfonate (AOS), which are commonly found in industrial and consumer products, including detergents. This study assessed acute (96-h) and subchronic (14-day) responses using antioxidant activity, protein levels, and histopathological changes in Tubifex tubifex exposed to different AOS concentrations (10% of the LC50, 20% of the LC50, and a control). Molecular docking was used to investigate the potential interactions between the key stress biomarker enzymes (superoxide dismutase, catalase, and cytochrome c oxidase) of Tubifex tubifex. Acute AOS exposure showed a concentration-dependent decrease in survival, and the general unified threshold (GUTS) model revealed that survivorship is linked to individual response patterns rather than random (stochastic) fluctuations. The GUTS model also revealed dose-dependent toxicity patterns in Tubifex tubifex exposed to α-olefin sulfonate (AOS), with adaptive mechanisms at lower concentrations but significant increases in mortality beyond a certain threshold, emphasizing the role of the AOS concentration in shaping its toxicological impact. Exposure to AOS disrupted antioxidant activity, inducing oxidative stress, with GST and GPx showing positive associations with surfactant concentration and increased lipid peroxidation (elevated MDA levels); moreover, AOS exposure decreased protein concentration, signifying disturbances in vital cellular processes. Histopathological examinations revealed various tissue-level alterations, including cellular vacuolation, cytoplasmic swelling, inflammation, necrosis, and apoptosis. Molecular docking analysis demonstrated interactions between AOS and enzymes (-catalase, superoxide dismutase, and cytochrome c oxidase) in Tubifex tubifex, including hydrophobic and hydrogen bond interactions, with the potential to disrupt enzyme structures and activities, leading to cellular process disruptions, oxidative stress, and tissue damage. According to the species sensitivity distribution (SSD), the difference in toxicity between Tilapia melanopleura (higher sensitivity) and Daphnia magna (low sensitivity) to AOS suggests distinct toxicokinetic and toxicodynamic mechanisms attributable to more complex physiology in Tilapia and efficient detoxification in Daphnia due to its smaller size. [ABSTRACT FROM AUTHOR]

Featured Application: This research underscores the effectiveness of using seashells and ceramic bricks as substrates in vertical flow CW for greywater treatment. The findings are particularly relevant for rural and semi-arid regions, where these low-cost, sustainable systems can enhance water quality. The study also provides valuable insights into optimizing macrophyte age and substrate materials, offering practical solutions for decentralized wastewater treatment in underserved areas. This technology can be particularly beneficial for decentralized wastewater treatment in communities with limited access to advanced infrastructure, offering a practical solution for improving water quality and sustainability in resource-constrained environments. Constructed wetland (CW) systems have been recognized as a sustainable technology for wastewater treatment that can be easily integrated into the local natural environment, offering both low cost and high efficiency. In this study, synthetic greywater was treated using a vertical subsurface flow CW operated in batch mode with 7-day cycles across two phases, operated in parallel: I, non-vegetated, and II, vegetated, with Echinodorus subalatus. The mixed filter bed was composed of seashells, ceramic brick fragments, and sand. No statistically significant differences (p > 0.05) were observed between the non-vegetated and vegetated phases for most parameters. The removal efficiencies of organic matter, anionic surfactants, and total phosphorus in the non-vegetated versus vegetated phases were (91.0 ± 3.8)% versus (94.0 ± 1.1)%; (71.9 ± 14.1)% versus (60.0 ± 9.5)%; and (35.2 ± 4.6)% versus (40.2 ± 15.5)%, respectively. Phosphorus removal exceeded values reported in the literature for both phases, primarily due to the calcium present in the seashells, which increased the electrical conductivity and hardness of the effluent compared to the influent. The macrophyte exhibited leaf desiccation, possibly due to contact with greywater and its young age (30 days), which may have negatively impacted the system's performance during the vegetated phase. [ABSTRACT FROM AUTHOR]

Conventional strategies for highly selective and active hydrogen peroxide (H2O2) electrosynthesis primarily focus on catalyst design. Electrocatalytic reactions take place at the electrified electrode–electrolyte interface. Well‐designed electrolytes, when combined with commercial catalysts, can be directly applied to high‐efficiency H2O2 electrosynthesis. However, the role of electrolyte components is equally crucial but is significantly under‐researched. In this study, anionic surfactant n‐tetradecylphosphonic acid (TDPA) and its analogs are used as electrolyte additives to enhance the selectivity of the two‐electron oxygen reduction reaction. Mechanistic studies reveal that TDPA assembled over the electrode–electrolyte interface modulates the electrical double‐layer structure, which repels interfacial water and weakens the hydrogen‐bond network for proton transfer. Additionally, the hydrophilic phosphonate moiety affects the coordination of water molecules in the solvation shell, thereby directly influencing the proton‐coupled kinetics at the interface. The TDPA‐containing catalytic system achieves a Faradaic efficiency of H2O2 production close to 100% at a current density of 200 mA cm−2 using commercial carbon black catalysts. This research provides a simple strategy to enhance H2O2 electrosynthesis by adjusting the interfacial microenvironment through electrolyte design. [ABSTRACT FROM AUTHOR]

Natural biopolymers become increasingly attractive as bio-based alternatives to petrol-based rheological modifiers, especially in personal care applications. However, many polysaccharides exhibit undesired properties in cosmetic applications such as limited viscosifying characteristics, unpleasant sensory properties, or incompatibility with certain formulation compounds. Here, a comprehensive rheological analysis of non-decorated acetan-like heteroexopolysaccharides derived from two Kozakia baliensis strains was performed in selected surfactant formulations. The results were compared to native xanthan gum and a genetically engineered xanthan variant, Xan∆ gumFGL , which lacks any acetyl- and pyruvyl moieties and whose rheological properties are unaffected by saline environments. All four polysaccharides displayed a highly similar rheological performance in the non-ionic surfactant lauryl glucoside, while the rheological properties differed in amphoteric and anionic surfactants cocamidopropyl betaine and sodium laureth sulfate due to minor changes in side chain composition. Polysaccharide precipitation was observed in the presence of the cationic surfactant. Nevertheless, the native heteroexopolysaccharide derived from K. baliensis LMG 27018 shows significant potential as a salt-independent rheological modifier compared to the genetically engineered Xan∆ gumFGL variant. In addition, blends of heteroexopolysaccharides from K. baliensis and several galactomannans displayed synergistic effects which were comparable to native xanthan gum-galactomannan blends. This study shows that heteroexopolysaccharides of K. baliensis are capable of further extending the portfolio of bio-based rheological modifiers. [ABSTRACT FROM AUTHOR]

For agricultural countries in Aisa, rice straw is a waste product, but also a valuable bioresource, with its recycling methods often drawing widespread attention. In this study, a novel multicomponent extraction method was proposed to perform comprehensive extraction of holocellulose and lignin from rice straw powder (RSP), resulting in modified rice straw powder (MRSP) with different micro‐morphologyies. The results indicate that the cosolvent tetraethylammonium chloride (TEAC) is more effective for extracting holocellulose and lignin compared to others, and different surfactants have decisive impacts on the extraction of holocellulose and lignin from RSP. Among them, anionic surfactants aid in the extraction of holocellulose, with sodium allylate sulfonate (SAS) being superior due to its greater changes in allyl polarity. Conversely, cationic surfactants facilitate the extraction of lignin, with octadearyl trimethyl ammonium chloride (OTAC) being superior due to the length of its alkyl‐carbon chain. And the quantized contribution of hydrophilic and hydrophobic groups of surfactants to the extraction of holocellulose and lignin, as well as, the different micromorphology of MRSP is obtained. Additionally, compared to the traditional PU (polyurethane) modified by eucalyptus wood powder (EWP/PU), the MRSP was used to prepare a series of biomass composite polyurethane synthetic leather (MRSP/PU), its tensile strength and peel strength of MRSP/PU coatings are greatly enhanced at the feedstock of 18 %. [ABSTRACT FROM AUTHOR]

Formation damage caused by organic contaminates is one of the most important issues that undermine well injectivity and productivity. Anionic surfactants are commonly used to mobilize the organic contaminates trapped by capillary forces. The electrostatic repulsion between anionic surfactant heads reduces the surfactant density at the oil-water interface, consequently reducing the interfacial efficiency. In this paper, a novel surfactant blend of anionic-cationic surfactants (Sa/c) was designed and showed much higher efficiency than traditional ones because of the strong electrostatic attraction between anionic and cationic surfactants. The oil-water interfacial tension (IFT) was reduced to 3 × 10−4 mN/m, and the viscosity of crude oil was reduced by 92%. In addition, the freezing point of the residual oil was decreased by 20.9%. Moreover, Sa/c altered the wettability and inhibited the clay swelling. Field applications were conducted in sandstone reservoirs at temperatures of about 120 °C and permeabilities below 10 mD. The average injection pressure drops were greater than 30%. The findings of this study can help for better understanding the advantages of Sa/c with high interfacial activity and revealed that formation damage caused by the organic contaminates in high temperature and low permeability sandstone reservoirs can be effectively remediated by this novel surfactant blend. [ABSTRACT FROM AUTHOR]

In the foundry industry, casting sand cores require high and low peak and residual strengths, respectively, to achieve comprehensive optimal mechanical performance. The peak and residual strengths of sand cores are positively related, highlighting the criticality of balancing them. Thus, an innovative approach comprising the incorporation of anionic surfactants into the silicate binder was introduced to balance both factors. Additionally, the investigation of the effects of the anionic surfactants on the physical properties of the silicate binder, including its colloidal stability, surface tension and adhesion, revealed that four different anionic surfactants reduced the surface tension and adhesion of the silicate binders and reduced the residual strength of the silicate-bonded sand cores. Among them, 0.10 wt% lauryl ether phosphate reduced the surface tension and adhesion of the adhesive by 49.64 and 112 mN/m, respectively, and reduced the residual strength of the sand core by 0.035 MPa. However, increasing the dosage did not further reduce the residual strength of the sand core, although it continued to reduce its peak strength. Therefore, during silicate binder modification with anionic surfactants, the dosage of the anionic surfactant must be kept at ≤0.10 wt%, as this dosage exerted the most comprehensive optimal modification effect, which was attributable to the adsorption of anionic polymers onto the surface of the silicate aggregates. This adsorption weakened the network structure of the silicate aggregates and imparted the sand cores with appropriate mechanical properties during casting. [ABSTRACT FROM AUTHOR]

With the increasing emphasis on environmental protection, there is a growing focus on the synthesis of water‐solvent self‐emulsifying sizing agents. In this study, five types of anionic polyester sizing agents with varying molecular weights were synthesized to explore the effect of molecular weight on the interfacial bonding strength of carbon fiber (CF) reinforced vinyl resin composites. The results demonstrated that the molecular weights of the synthesized sizing agents were precise; the particles in the sizing agents were nanometer‐sized, monodisperse, and exhibited high thermal stability. When the molecular weight was 8000, it exhibited optimal wettability for CF, leading to a substantial improvement in the interlaminar shear strength, reaching 71.8 MPa, which represents a significant increase of 22.7% compared with commercial CFs (CFF). Additionally, the interfacial shear strength was maximized at 13.23 MPa, which was significantly increased by 14.2% compared with CCF. These significant improvements in surface properties and mechanical performance were attributed to the excellent wettability of the CF surface, effective spreading performance of the sizing agent, the presence of double bonds in the sizing agent facilitating reactions with free radicals on the CF surface, and the residual double bonds further undergoing curing with the vinyl resin, promoting the reinforcement of interface bonding. [ABSTRACT FROM AUTHOR]

In this work, sodium dodecyl and tetradecyl glycoside sulfate (APGS-Na) was synthesized by sulfating dodecyl and tetradecyl glycoside (APG1214) with chloro-sulfonic acid (CSA). The product was then characterized using FT-IR, 1H NMR, MS, and elemental analysis. Response surface methodology (RSM) was used to explore the sulfation modification conditions in order to achieve the maximum APG1214 conversion rate (84.79% with the molar ratio of CSA to APG1214: 2.17:1, reaction temperature: 16 °C, and reaction period: 2 h). Further studies were performed to establish the relationship between the pertinent structure and physicochemical characteristics, such as Krafft point, equilibrium surface tension, dynamic surface tension, aggregation behavior of micelles and lyotropic liquid crystals (LLCs), as well as application characteristics like foam property, emulsification, detergency, and irritability. The results demonstrated that the Krafft point of APGS-Na was below 0 °C, and the surface tension (γcmc) was 39.4 mN·m−1 when the critical micellar concentration (CMC) was 2.40 g·L−1. At low concentration, the adsorption process was controlled by a diffusion step, different to a mixed kinetic-diffusion adsorption mechanism at high concentration, can form large size micelles and attractive LLCs in water. Moreover, the surfactant is nonirritant, with excellent foaming and decontamination capability. Accordingly, APGS-Na is expected to be widely used in diverse fields as a green anionic glycoside surfactant. APGS-Na (resistance to hard water, no irritation) was synthesized and characterized. The optimization of APG1214 Sulfurization reaction conditions using RSM. Adsorption kinetic mechanisms of APGS-Na aqueous solution during the adsorption process. APGS-Na can form rod micelles and interesting lyotropic liquid crystals. [ABSTRACT FROM AUTHOR]

The use of foam injection as an enhanced oil recovery (EOR) technique has been suggested since the 1960s to address issues with gas injection. Foam is composed of gas, water, and surfactant, which is utilized to stabilize the foam. This study investigates the synergy effect of anionic surfactant and two zwitterionic surfactants on enhancing solution stability. The anionic surfactant used is sodium dodecyl sulfate, while the chosen zwitterionic surfactants are cocamidopropy hydroxy sultine and Cocamido Propyl Betaine. Analyzing the images of the generated foam showed that initially, the small and uniform bubbles are formed in all concentrations. The foam size is then increased and in concentrations higher than a critical value, the bubbles grow faster which is likely due to the formation of micelles and deposition of surfactants. This leads to early collapse of the foam structure. The quantitative half-life results approved that the most optimal compound was obtained with equal proportions of sodium dodecyl sulfate and Cocamido Propyl Betaine with concentration of 3 wt% (1:1 ratio, 0.15 wt%-0.15 wt%). To quantitatively study on foam characteristics, conductivity and interfacial tension tests were performed. The results of the conductivity tests showed that micelles were formed in concentrations of more than 0.3 wt%. Interfacial tension measurements revealed that addition of a small amount of surfactants to the base solution, led to reduction of the interfacial tension value from 29.2 (mN/m) in base solution to less than 1 mN/m for solutions treated with surfactant. [ABSTRACT FROM AUTHOR]

According to the first principle, the SDS anions are preferentially adsorbed on the (0 0 2) surface of the Zn anode, forming a protective layer which prevents the adsorption of free water molecules and modifies the electrode/electrolyte interface. The SDS additive significantly inhibits the contact of water molecules with the interface, reduces the generation of by-products, and effectively prevents the growth of dendrites. Consequently, with the assistance of SDS additives, the Zn||Zn symmetrical battery sustains a long cycle life for 2000h. [Display omitted] Aqueous zinc-ion batteries are emerging as powerful candidates for large-scale energy storage, due to their inherent high safety and high theoretical capacity. However, the inevitable hydrogen evolution and side effects of the deposition process limit their lifespan, which requires rational engineering of the interface between anode and aqueous electrolyte. In this paper, an anionic surfactant as electrolyte additive, sodium dodecyl sulfonate (SDS), is introduced to deliver highly reversible zinc metal batteries. Unlike traditional surfactants, the solvation structure is not affected by SDS, which tends to adsorb on the (0 0 2) crystal plane of Zn with the purpose of effectively limiting the water molecules adsorption. Attributed to the natural hydrophobic part of SDS, a dynamic electrostatic shielding layer and a unique hydrophobic interface are constructed on the anode. Assisted by the above merits, the adverse surface corrosion, hydrogen evolution and dendrite growth are significantly inhibited without the sacrifice in the deposition kinetics of Zn ions. As a result, the Zn||Zn symmetric batteries demonstrate an increased cycle life of 2000 h (1 mA cm−2, 1 mA h cm−2) with the presence of SDS additive. Such strategy provides a new avenue for the developing advanced electrolytes to be applied in aqueous energy storage systems. [ABSTRACT FROM AUTHOR]

[Display omitted] The formation of adducts via urea interaction with distinct classes of surfactants (cationic, anionic, nonionic, and zwitterionic), leading to their assembly into lamellar structures and subsequent formation of hydrogels. The characteristics of these hydrogels are associated with both, the length of the alkyl chain, and the specific head group of the surfactant molecules. Characterization of adduct formation was conducted using Wide-Angle X-ray Scattering (WAXS), while Small-Angle X-ray Scattering (SAXS) was employed to probe the subsequent assembly into lamellar structures. The kinetics of hydrogel formation were assessed through rheological measurements and observed thermal transitions utilizing Differential Scanning Calorimetry (DSC). The investigation revealed a universal propensity for hydrogel formation across all surfactant classes. The formation arises from the interactions between urea molecules via hydrogen bonding, forming adducts around the surfactant chains. In sequence, the adducts self-assemble in lamellae. This process constructs the intricate three-dimensional network characteristic of the hydrogel. Furthermore, the kinetics of hydrogel formation, and their rheological properties under equilibrated conditions, were found to be significantly influenced by the nature of the polar head group of the surfactant molecules. This is the first evidence on the formation of adducts of urea with classes of surfactants. As they are common components in cosmetic, supramolecular hydrogels have high potential to be used in formulations. [ABSTRACT FROM AUTHOR]

Selecting the appropriate surfactant as a foaming agent is crucial in the production of foamed concrete. In this study, multiple technological approaches were employed for the investigation of the effect of three different types of surfactants as foaming agents; the approaches included surface tension measurement, zeta potential analysis, spectrophotometry, and nanoindentation. The results showed that the surface activity, solution viscosity, and environmental pH all influenced the generation and stability of foam in foaming agents. The adsorption process of surfactants onto cement particles was complex and could be effectively explained using the double-layer theory. The adsorption of anionic surfactant molecules on cement particles significantly altered the zeta potential, up to −17 mV, with an adsorption efficiency over 10 times greater than that of cationic surfactants and more than 5 times greater than that of nonionic surfactants. Furthermore, after cement hardening, the mechanical properties of the resulting pores were notably improved due to the presence of adsorbed anionic surfactants, and the maximum compressive strength could exceed 10 MPa. [ABSTRACT FROM AUTHOR]

Soil conditioning is essential for addressing the stratum applicability problem of earth pressure balance (EPB) shields. Under high water pressures, EPB shields spew water and soil when excavating coarse-grained strata. Typically, foam combined with polymers and slurry is used to solve spewing. However, in current techniques, slurry, foam, and the other agents are mixed with soil separately, their synergistic effect is seldom realized. In this study, an anionic surfactant was used to foam in bentonite slurry to form bubble–slurry to maximize the synergy between bubbles and slurry. The slump, volume stability, and permeability test of bubble–slurry-conditioned sand was conducted to examine the conditioning effect, and the stratum applicability of bubble–slurry was determined from the perspective of permeability. It was found that the conditioning effect of bubble–slurry in coarse gravel soil was excellent and could expand the applicability of EPB shields. The main stabilization mechanism of bubble–slurry is that bentonite particles provide a space barrier for bubbles. And three seepage modes of bubble–slurry-conditioned sand were innovatively defined, and the occurrence conditions of the three seepage modes were analyzed according to the permeability coefficient of sand, initial dynamic shear force of bubble–slurry, and hydraulic gradient. [ABSTRACT FROM AUTHOR]

Copyright of Iraqi Journal of Chemical & Petroleum Engineering is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sample preparation is the first and most important step of analytical methods, especially for the analysis of complex matrices such as soil. A new and simple microextraction method termed solvent bar microextraction (SBME) was able to provide good results in terms of precision, accuracy, selectivity, and enrichment factor. Here, for the first time, a new analytical method based on ion-pair solvent bar microextraction (IP-SBME) in combination with UV–Visible spectrophotometry was introduced for the simple determination of paraquat (PQ) in soil samples. In this two phase process, an anionic surfactant was added initially into the donor solution to form a hydrophobic ion pair with the cationic analyte. Thereupon, the ion pair formed was enriched into organic solvent immobilized in the pores and lumen of the hollow fiber (HF) and finally back washed with methanol. Significant parameters affecting the proposed method were optimized as pH 6, concentration of SDS 5 mM, stirring rate of 500 rpm, time of extraction 15 min, without addition of salt. Under the optimized extraction conditions, the method showed a good linear dynamic range (1–2000 μgL−1) with a lower limit of detection (0.3 μgL−1) and excellent preconcentration factor (PF = 355.34). Finally, the proposed method was successfully applied for the determination of PQ in soil samples. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For industrial applications of self-assembled wormlike micelles, measurement and characterization of a micellar material's microstructure and rheology are paramount for the development and deployment of new high-performing and cost-effective formulations. Within this workflow, there are significant bottlenecks associated with experimental delays and a lack of transferability of results from one chemistry to another. In this work, we outline a process to predict microscopic and thermodynamic characteristics of wormlike micelles directly from rheological data by combining a more robust and efficient fitting algorithm with a recently published constitutive model called the Toy Shuffling model [J. D. Peterson and M. E. Cates, J. Rheol. 64, 1465–1496 (2020) and J. D. Peterson and M. E. Cates, J. Rheol. 65, 633–662 (2021)]. To support this work, linear rheology measurements were taken for 143 samples comprising a common base formulation of commercial sodium lauryl ether sulfate, cocamidopropyl betaine, and salt (NaCl). The steady state zero shear viscosity evident in linear rheology was measured in duplicate via direct steady and oscillatory shear experiments. Fitting the collected data to the model, we found trends in the microstructural and thermodynamic characteristics that agree with molecular dynamics simulations. These trends validate our new perspective on the parameters that inform the study of the relationship between chemical formulation and rheology. This work, when implemented at scale, can potentially be used to inform and test strategies for predicting self-assembled micellar structures based on chemical formulation. [ABSTRACT FROM AUTHOR]

We use molecular dynamics simulations to study the frictional response of monolayers of the anionic surfactant sodium dodecyl sulfate and hemicylindrical aggregates physisorbed on gold. Our simulations of a sliding spherical asperity reveal the following two friction regimes: at low loads, the films show Amonton's friction with a friction force that rises linearly with normal load, and at high loads, the friction force is independent of the load as long as no direct solid–solid contact occurs. The transition between these two regimes happens when a single molecular layer is confined in the gap between the sliding bodies. The friction force at high loads on a monolayer rises monotonically with film density and drops slightly with the transition to hemicylindrical aggregates. This monotonous increase of friction force is compatible with a traditional plowing model of sliding friction. At low loads, the friction coefficient reaches a minimum at the intermediate surface concentrations. We attribute this behavior to a competition between adhesive forces, repulsion of the compressed film, and the onset of plowing. [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]

Objective: Liposomes are often used in cosmetics since they are naturally derived and have excellent texture enhancing capabilities. However, when preparing them by using phospholipids with unsaturated acyl groups, they easily suffer from oxidative degradation. Accordingly, hydrogenated phospholipids are preferred, however, it is difficult to prepare stable liposomes due to its high gel‐liquid crystalline phase transition temperature. On the other hand, although dialkyl dimethyl ammonium type cationic surfactants are widely known to form vesicles, they have rarely been used for skincare products except for water‐in‐oil type emulsion creams stabilized by organically modified clay minerals. We decided to overcome all of the problems above through ionic complex vesicles formed by double‐tailed cationic and anionic surfactants. Methods: Distearyl dimethyl ammonium chloride (DSAC) and sodium dilauramidoglutamide lysine (DLGL) were selected as cationic and anionic surfactants, respectively. Differential scanning calorimetry (DSC) and small‐ and wide‐angle X‐ray scattering (SWAXS) measurements were performed to confirm the DSAC/DLGL/water ternary phase diagram. Newly developed ionic complex vesicle formation was confirmed by cryogenic transmission electron microscopy (cryo‐TEM). The adsorbed cosmetic film structure on the skin in vivo was evaluated through the polarized infrared external reflection (PIR‐ER). Finally, a cosmetic lotion formula was developed and the vesicle size was determined by dynamic light scattering (DLS). Results: DSC and SWAXS data indicated that stable vesicles could be obtained at a molar ratio of DLGL to DSAC = 6:4. At this molar ratio, multi lamellar vesicles with diameters less than 100 nm were observed through cryo‐TEM. PIR‐ER data revealed that the developed vesicles formed a highly perpendicular orientation to the human skin surface. We have succeeded in formulating a cosmetic lotion containing developed vesicles with a mean diameter of 63.2 nm, which was stable over 1 month at 0, 37, and 50°C. Conclusions: Our newly developed vesicles can be easily obtained through a coagulation process. Also, the adsorbed film structure supported by PIR‐ER experiments implies that the developed lotion has an excellent texture that is the same as cosmetic lotions containing liposomes. Therefore, it's possible that this ionic complex vesicle could take the place of liposomes. [ABSTRACT FROM AUTHOR]

This work investigated in‐situ synthesis of porous silica‐nickel‐ruthenium composite catalysts for hydrolysis of ammonia borane. The precursors were prepared with an anionic surfactant, sodium dodecyl sulfate (SDS), to form porous structure in the precursor particles, and the precursors was treated in aqueous solution including sodium borohydride and ammonia borane for in‐situ process to parallelly activate and use the catalysts for hydrolysis of ammonia borane. The result of TEM and nitrogen sorption measurements suggested that the primary particle size of the in‐situ synthesized catalysts decrease with increasing the amount of SDS and sodium chloride as the additive for controlling the primary particle size probably because of the effect of sodium ions to inhibit nuclei growth of the primary particles. From the EDS analyses, the composition of active nickel and ruthenium contents increased with increasing the amount of SDS and sodium chloride except for the highest amount of SDS probably because of adsorption of the metal cations with the excess amount of the surfactant anion to decrease the amount of the metal cations including the catalyst. The in‐situ synthesized catalyst including small size primary particles and high nickel and ruthenium content tended to exhibit high activity for hydrolysis of ammonia borane. [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]

Objective In order to solve the problems such as too stable traditional foam and difficulty in defoaming.Method Using N-dodecyl-1,3-propanediamine and temperature and salt tolerant anionic surfactant to prepare a CO2 responsive temperature and salt tolerance composite foam system, and uses molecular simulation to explore the stability and response mechanism of the composite foam. Results Results show that N-dodecyl-1,3-propanediamine has good protonation and salt tolerance properties. However, its temperature tolerance is poor, and it does not have response performance. After compounding with sodium dodecyl sulfate (SDS) and sodium dodecyl sulfate, the foaming speed at high temperature is increased by 40%, the foam duration is 3.17 times longer than that before compounding, the temperature resistance is significantly improved, and the foam is defoamed rapidly within a short period after passing CO2. Molecular simulation studies reveal that the S atomic groups contained in SDS will combine with the positively charged N atomic groups in C12N(CH3)N(CH3)2 and lose surface activity, resulting in poor stability of the foam, which is also responsible for the responsive defoaming. Conclusion The composite system has good temperature and salt resistance and responsiveness, and can realize responsive defoaming after foam drainage and gas production in harsh environments which has broad application prospects. [ABSTRACT FROM AUTHOR]

In the present work, the volumetric and conductometric studies to find the interactions between amino acids DL-Valine and DL-Serine with cationic and anionic surfactants, cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulphate (SDS) in aqueous solutions at different temperatures and atmospheric pressure were carried out. The effect of pre- and post-micellar concentrations of surfactants on the physicochemical properties was also studied. The densities measured experimentally were used to calculate the thermodynamic parameters such as the apparent molar volumes, ϕv, partial molar volumes, , transfer volumes, (tr), and partial molar expansibilities, at temperatures from 288.15 to 303.15 K while the conductivity data obtained at different temperatures from 293.15 to 318.15 K were used to obtain the molar conductivities () as well as limiting molar conductivities () from specific conductivities (κ) which reflect the interaction prevailing within the studied systems. In addition, the UV-visible absorption spectroscopy at 298.15 K has also been performed in the presence of fluorescein to study the interaction within above mentioned systems. [ABSTRACT FROM AUTHOR]

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has recently gained interest as a potential candidate for small-scale thermoelectric conversion because of the facile doping, solution processability, and flexibility. However, the practical applications of PEDOT:PSS are limited by its comparatively low figure of merit (ZT) compared with inorganic thermoelectric materials. Herein, to further improve the thermoelectric properties of PEDOT:PSS, we investigated the role of the addition of surfactants, sodium dodecyl sulfate, sodium dodecyl benzenesulfonate (SDBS) or Triton X-100, to the PEDOT:PSS free-standing films on their thermoelectric properties. We showed that the addition of the surfactant improved the film crystallinity, significantly improving the electrical conductivity. The highest conductivity was obtained for anionic surfactant SDBS at a 0.94 wt% concentration. Moreover, the inclusion of the surfactant reduced the thermal conductivity while maintaining a relatively constant Seebeck coefficient, consequently improving the ZT value. Furthermore, a flexible thermoelectric device crafted from the as-fabricated PEDOT:PSS/SDBS sheets was developed to explore the potential applications of wearable electronics using low-grade thermal energy. Overall, we indicate the significance of surfactants in enhancing the thermoelectric properties of free-standing PEDOT:PSS films in this study. [ABSTRACT FROM AUTHOR]

The interactions of polyelectrolyte poly (sodium styrene sulfonate or NaPSS) and anionic surfactants, sodium glycodeoxycholate (SGDC) and sodium tetradecyl sulfate (STS), as well as their combination (SGDC + STS) at different mole fraction ratios, were investigated using surface tension analysis. In the SGDC + STS binary mixture, when the amount of NaPSS (0.005–0.03%) increased from α SGDC 0.0 to 1.0, increasing the critical micellization concentration (cmc) of the mixtures. The minimum cmc values were found from 0.833 to 1.480 mmol L−1 in the presence of 0.03% of NaPSS. Clint, Rubingh, Motomura, and Rodenas approaches were used to evaluate the ideal cmc, activity coefficients (fi), interaction parameter (–β), micellar compositions (x), and ideal micellar composition of (xid) of SGDC + STS mixtures. Synergism has been demonstrated by the experimental values of c0m being lower than the ideal values in water. Moreover, by adding NaPSS from 0.005 to 0.03%, the synergism interaction was eliminated and antagonism behavior was developed. The standard Gibb's free energy of micellization ( Δ G m 0) and surface excess (Γ) and surface area per absorbed molecules (Amin) was decreased or increased depending on NaPSS amount in the SGDC + STS mixture with varying a SGDC . [ABSTRACT FROM AUTHOR]

Taitema Lake, situated at the terminus of the Tarim River Basin in Northwest China, represents a crucial ecological resource impacted by climate variability and anthropogenic interventions. In this study, we investigate the dynamic changes in Taitema Lake's area and water quality resulting from the implementation of an ecological water transfer project in 2000. Leveraging Landsat remote sensing data and comprehensive water quality monitoring, we analyzed the relationship between lake area variations and shifts in water quality parameters. Notably, our findings reveal a significant increase in Taitema Lake's area from 9.4 km2 in 2000 to 320 km2 in 2013. Concurrently, water quality indicators exhibited marked fluctuations, with total salt content ranging from 45,323.6 mg/L in 2000 to 970.4 mg/L in 2010 before increasing to 14,586.3 mg/L by 2014. Furthermore, a linear regression analysis highlights the moderate positive correlation between lake area and mineralization (R2 = 0.506) and sodium levels (R2 = 0.4907). Additionally, chloride (R2 = 0.5681) and sulfate (R2 = 0.6213) concentrations demonstrated a strong negative correlation with the lake area, indicative of a dilution effect. Furthermore, a comparison of water quality indicators between the years of minimum (2008) and maximum (2013) lake area underscores improvements in pH, chemical oxygen demand, and anionic surfactant concentrations as the lake area increased. Our study provides valuable insights into the effectiveness of ecological water management strategies in restoring and maintaining the ecological health of Taitema Lake, thereby informing evidence-based decision-making for the sustainable management of freshwater resources in arid environments. [ABSTRACT FROM AUTHOR]