Ether Sulfate Research Articles

Compound Surfactant System with Superior Oil Displacement Performance: Balanced Synergistic Effects from Oil-Water and Oil-Solid Interfaces.

The oil film formed by the adhesion of crude oil to the resin-asphalt adsorption layer is difficult to peel off due to the strong oil-solid interaction, which severely limits further improvements in oil recovery. Although conventional compound oil displacement systems can effectively reduce oil-water interfacial tension, facilitate oil droplet deformation, and alleviate the Jamin effect, they are insufficient in controlling the wettability of oleophilic rock surfaces. In this paper, sodium nonylphenol polyoxyethylene ether sulfate (NPES) and sodium lauric acid ethanolamine sulfonate (HLDEA) were compounded to construct an efficient oil displacement system that simultaneously achieves wettability control of lipophilic surfaces and ultralow oil-water interfacial tension. The HLDEA + NPES system reduces the interfacial tension to 3.8 × 10-3 mN·m-1 and enhances surface wettability control, with an underwater oil contact angle of 157.2°. The compound system can remain stable at high temperatures (up to 110 °C) and high salinity (1 × 105 mg·L-1 NaCl and 7 × 103 mg·L-1 Ca2+). The oil recovery rate increases by 28.7% compared with water flooding and surpasses by 7.8% compared with a commercial ultralow interfacial tension system (10-4 mN·m-1). The synergistic effect of HLDEA and NPES in the oil/water interface increases the interfacial modulus and phase angle, thereby improving the stability of the interfacial film. The synergistic adsorption of HLDEA and NPES in the oil/water interface creates a denser adsorption layer, achieving enhanced wettability control. The HLDEA + NPES system balances the interactions from the oil-water and oil-solid interfaces, achieving a synergistic effect of oil film peeling and oil droplet migration, thereby significantly improving the recovery rate.

Nontarget screen and identify sulfate and sulfonate surfactants in personal care products using UHPLC-Q-Orbitrap-HRMS based on fragmentation characteristics and sulfur isotopologue pattern.

Sulfate and sulfonate compounds are extensively used as anionic surfactants in personal care products (PCPs), which might pose adverse potential to human health. However, available research mostly identified certain subsets of sulfated and sulfonated surfactants based on target analysis. In this study, we developed a comprehensive nontarget strategy for identification of sulfated and sulfonated surfactants in PCPs using UHPLCHRMS supplemented by an in-lab R script based on characteristic fragment ions and sulfur isotope patterns. A total of 20 sulfate and 12 sulfonate surfactants of confidence level 3 and above were identified in the range of alkyl chain length from C12 to C26 with 0-7 ethoxy groups and molecular weights of 200-600 Da in the PCP samples. The sulfates included 4 alkyl sulfates and 16 alkyl ether sulfates. In addition to commonly reported 4 alkyl benzene sulfonates, this study identified eight sulfonate surfactants for the first time, which were 3 alkyl sulfonates, 3 methyl ammonium sulfonates, and 2 bis-sulfonate sulfonates in the PCPs. Interestingly, 22 sulfate and sulfonate compounds were identified in the negatively labeled PCP samples which were not supposed to contain sulfate and sulfonate surfactants. The results demonstrated robustness of the developed nontarget analyzing strategy in identifying and characterizing sulfate and sulfonate surfactants and consequently providing guidance for management and regulation of chemical addition in PCPs to ensure safe use.

Synergistic effects of mediated by different 1,2-epoxybutane addition numbers butoxylated alkyl block alcohol ethers and SDS in mixed systems

In this study, nonionic surfactant butoxylated alkyl block ether (AE9Bn) and anionic surfactant sodium dodecyl sulphate (SDS) with different BO additions were mixed at different molar ratios to make a hybrid system. The interaction parameters and aggregation behaviors of the blended systems were investigated by observing the average direct particle drop distribution and microscopic aggregates in combination with the results of static surface tension tests of the blended systems. The diffusion process of the mixed systems was investigated using dynamic surface tension tests. The dynamic contact angle and foam properties of the solutions of the mixed systems were also studied. Finally, based on the experimental results, it was concluded that the mixed system of AE9Bn (n=2,5) and SDS formed a synergistic effect that significantly led to a decrease in CMC, with an increase in the number of BO additions leading to a more significant decrease in CMC. The mixed system is a non-ideal mixed system, which is consistent with the kinetic mechanism of mixing and diffusion. The hybrid system has good aggregation pattern and wetting diffusion behavior and has low foam stability due to slow maturation of Ostwald.

Analysis of Spontaneous and Dynamic Imbibition Characteristics of Silica-Based Nanofluid in Microscopic Pore Structure of Tight Oil Reservoirs.

Imbibition behavior plays a crucial role in tight oil reservoir development, to increase tight oil production, a novel sodium lauryl ether sulfate (SLES) nanofluid was developed. Spontaneous and dynamic imbibition performance of nanofluid and the relative influencing factors were systematically investigated using the online low-field nuclear magnetic resonance (LF-NMR) technique. The microscopic mobilization characteristics and mechanism of nanofluid-enhanced matrix crude oil recovery in tight oil reservoirs were further explored. The experimental results showed that the proposed SLES nanofluid achieved the highest imbibition efficiency, and appropriate concentrations of nanoparticle and surfactant were helpful in enhancing the imbibition recovery. Excessive concentrations of chemical agents may block the tiny pores. A reasonable injection rate and shut-in time should be determined to fully leverage capillary forces for water phase imbibition and oil phase displacement as well as the displacement effect of the viscous force and increased water wetness of the rock surface provided by the nanofluid. In addition, NMR T2 cutoff was applied to distinguish the imbibition and displacement regions during dynamic imbibition process. The pore sizes corresponding to the T2 cutoff values after nanofluid and deionized (DI) water flooding were 0.6 and 5 μm, indicating that nanofluid considerably increased the movable crude oil in pores of tight oil reservoirs compared with DI water. Furthermore, imbibition behavior was dominant in micropores (<0.1 μm) and mesopores (0.1-1 μm), and displacement principally occurred in microfractures and macropores. Finally, the underlying mechanisms responsible for nanofluid enhanced oil recovery were related to wettability alteration, capillary pressure, and viscous force. This work provides further understanding of spontaneous and dynamic imbibition when employing nanofluid in tight oil reservoirs.

Optimizing ex vivo penetration tests via quantitative confocal Raman spectroscopy: Impact of incubation time, skin hydration, surfactant treatment and UVA irradiation on caffeine distribution

Ex vivo penetration tests are important tools in cosmetic and pharmaceutical research. However, variability of experimental setups is challenging when reviewing literature. Different skin models, pre-treatments and experimental parameters render comparison difficult. Thus, our aim was to conduct ex vivo penetration tests using caffeine in different setups with varying incubation conditions (ambient vs. Franz cells, infinite vs. finite dose). Additionally, the impact of skin pre-treatment with different aggressors (surfactants, UVA irradiation) should be considered. Possible synergistic barrier damage of surfactants and UVA irradiation should be explored. Analysis was conducted using quantitative confocal Raman spectroscopy. Results showed that incubation time and extensive hydration (20 h in Franz cells) had the greatest impact on penetration behavior. Additional irradiation after pre-treatment with oil-in-water nanoemulsions showed no strong impact on caffeine penetration in general, irrespective of surfactant type. However, in case of sodium lauryl ether sulfate, a trend towards enhanced values was observed due to irradiation (1.3-fold). This suggests cumulative skin barrier damage of irritant surfactants and UVA irradiation, potentially due to stratum corneum alterations. Further studies using different irradiation regimens are planned to confirm this hypothesis.

Deposition of Nanometric Polymer-Surfactant Complexes Formed by Cationic Dextran: A Path to Sustainable Formulations.

The home and personal care industry is evolving toward more sustainable and environmentally friendly ingredients. Rinse-off personal care products rely on formation of polymer-surfactant complexes to drive deposition of benefit agents (e.g., conditioning oils, fragrances, etc.) onto the skin or hair. The most used natural polymers for this purpose are cationic guar (catGuar) and cationic hydroxyethyl cellulose (catHEC), and the complexation of these polymers with surfactants has been rigorously characterized. Various gaps still exist with these polymers, specifically low biodegradation and undesirable aquatic toxicity profiles. Modified dextran offers an exciting solution as a biodegradable polysaccharide with a high natural origin content. This paper aims to compare the morphology of polymer-surfactant complexes formed between a cationic dextran (catDex) polymer with mixtures of sodium lauryl ether sulfate (SLES) and cocamidopropyl betaine (CapB) to the morphologies of complexes formed between catGuar or catHEC and the same surfactants. Solutions were designed to mimic industrially relevant shampoos. Through a suite of complementary techniques, unique nanometric sized complexes were observed to form between catDex-SLES/CapB compared to the widely reported micrometer-sized coacervates (liquid-liquid phase separation) or precipitates (liquid-solid) formed in catHEC or catGuar-SLES systems. Using a quartz crystal microbalance with dissipation, the adsorption behavior of the catDex-SLES/CapB is characterized on a silica-coated sensor. The results show deposition throughout the dilution regime for catDex-SLES/CapB where the highest deposition is recorded with the undiluted rinsing formulation. This contrasts with catHEC-SLES/CapB and catGuar-SLES/CapB where the highest deposition is recorded in phase-separated regimes. This result was extended to performance testing on hair, confirming that the unique complexes formed by catDex can drive remarkably high levels of silicone deposition from rinse-off personal care products. This innovative approach of utilizing catDex-SLES/CapB complexes could enable design of more sustainable formulations that rely on polycation-surfactant nanocarriers.

Foam Properties Evaluation under Harsh Conditions: Implications for Enhanced Eco-Friendly Underbalanced Drilling Practices

Summary Foam drilling offers advantages such as reduced formation damage and faster drilling in underbalanced drilling (UBD) operations. The efficacy of foam drilling is influenced by factors including pressure, temperature, salt content, foam quality, and pH levels. However, a gap exists in the evaluation of foam properties under rigorous conditions, particularly those involving high pH and mixed salt environments common in drilling scenarios, highlighting the need for further research. In this study, a high-pressure, high-temperature (HPHT) foam analyzer and rheometer were employed to examine the stability and rheological behavior of ammonium alchohol ether sulfate (AAES) foam under simulated alkaline drilling conditions. The foaming solution, designed to replicate such conditions, consisted of synthetic seawater (SW) with a salt mixture totaling approximately 67.70 g/L and a 0.5 wt.% foaming agent adjusted to a pH of 9.5. This approach differs from the individual salt studies prevalent in existing literature and provides a unique perspective on foam stability and behavior. Driven by environmental sustainability considerations, the effects of eco-friendly surfactant AAES and various drilling fluid additives: polyanionic cellulose (PAC), carboxymethyl cellulose sodium (CMC), and xanthan gum (XG), were investigated for foam formulation. The apparent viscosity of the AAES foam was evaluated at different pressures and temperatures across varying shear rates. A consistent decrease in foam viscosity with increasing shear rates was observed, irrespective of pressure and temperature. An increase in foam viscosity was also noted with higher pressures (from 14.7 psi to 3,000 psi) at low shear rates, with values rising from 8.04 cp to 14.74 cp, and from 3.71 cp to 5.79 cp at high shear rates of 1,000 s⁻¹. Increasing foam quality from 65% to 85% resulted in significant improvements in viscosity, approximately 37% at low shear rates and about 79% at high shear rates. The introduction of additives to AAES foam at 1,000 psi and 90°C led to a substantial increase in viscosity, with PAC showing the most significant enhancement: 33.28 cp at low shear rates and 18.15 cp at high shear rates. Conversely, the viscosity of both base AAES foam and additive-enhanced foams decreased with rising temperatures, although PAC exhibited the greatest resistance to viscosity variations due to temperature changes. The addition of PAC also resulted in a notable increase in foam yield stress, potentially leading to more efficient cuttings transport and hole cleaning. Furthermore, foam stability was significantly improved by the additives, with XG and CMC doubling stability to 48 minutes, and PAC resulting in a threefold increase in half-life to 65 minutes. This study presents AAES and the tested additives as viable components for eco-friendly foam formulations, promoting enhanced properties suitable for UBD applications.

Experimental Investigations and MD Simulation on Nanoparticle-Enhanced CO2-Responsive Foam (NECRF): Implications on CO2-EOR.

CO2-responsive foam (CRF) is a highly promising candidate for CO2-enhanced oil recovery (CO2-EOR) because it displays higher stability than the surfactant-stabilized foam owing to the formation of robust wormlike micelles (WLMs) upon exposure to CO2. In this work, the nanoparticle-enhanced CO2-responsive foam (NECRF) was properly prepared using lauryl ether sulfate sodium (LES)/diethylenetriamine/nano-SiO2, and its interfacial properties and EOR potential were experimentally and numerically assessed, aiming to explore the feasibility and effectiveness of NECRF as a novel CO2-EOR technique. It was found that the interfacial expansion elastic modulus increased 6-fold after CO2 stimulation. The modulus continued to increase with the introduction of nano-SiO2 owing to the pronounced synergistic effect of WLMs and nanoparticles. In addition to increasing the viscosity of the foaming liquid, WLMs and nano-SiO2 enhanced the shearing resistance of the NECRF as well. Calculations demonstrated that both the coarsening rate and the size distribution uniformity coefficient of NECRF were markedly lower than that of the LES foam, which subsequently inhibited NECRF decay and greatly improved its dynamic stability. Besides, molecular dynamics simulation revealed that adding inorganic salts to NECRF could notably enhance the foaming performance due to the intensified hydration of surfactant head groups and reduced binding energy of neighboring molecules. Nuclear magnetic resonance-assisted core flooding experiments validated the exceptional capacity of NECRF to sweep the low-permeability region and improve the conformance profile. Overall, these findings may provide valuable insights into the development and application of novel materials and strategies for the CO2-EOR.

Electroactive biofilters outperform inert biofilters for treating surfactant-polluted wastewater by means of selecting a low-growth yield microbial community

Electrobioremediation is one of the most innovative disciplines for treating organic pollutants and it is based on the ability of electroactive bacteria to exchange electrons with electroconductive materials. Electroactive biofilters have been demonstrated to be efficient for treating urban wastewater with a low footprint; however, their application can be expanded for treating industrial wastewater containing significant concentrations (2.4 %vol) of commercial surfactants (containing lauryl sulfate, lauryl ether sulfate, cocamydopropyl betaine, and dodecylbenzene sulfonate, among others). Our electroactive biofilter outperformed a conventional inert biofilter made of gravel for all tested conditions, reaching removal rates as high as 4.5 kg COD/m3bed·day and withstood Organic Loading Rates as high as 9 Kg COD/m3·d without significantly affecting removal efficiency. The biomass accumulation reduced available bed volume in the electroactive biofilter just by 39 %, while the gravel biofilter decreased by 80 %. Regarding microbial communities, anaerobic and electroactive bacteria represented a substantial proportion of the total population in the electroactive biofilter. Pseudomonas was the dominant genus, while Cupriavidus, Shewanella, Citrobacter, Desulfovibrio, and Arcobacter were potential electroactive strains found in relevant proportions. The microbial community’s composition might be the key to understanding how high removal rates can coexist with limited biomass production, making electroactive biofilters a promising strategy to overcome classical biofilter limitations.

Synergistic inhibition mechanism of imidazolidine and sodium lauryl polyoxyethylene ether sulfate for Q235 steel in H2SO4 solution: Combining experimental measurements with theoretical calculations

The synergistic inhibition mechanism of imidazolidine (IM) with sodium lauryl polyoxyethylene ether sulfate (SLPES) for the corrosion of Q235 steel in H2SO4 solution was systematically studied by experimental and theoretical methods. The results show that there is a synergism between IM and SLPES with a maximum inhibition efficiency of 94.5 %. IM/SLPES retards both anodic and cathodic reactions to more extent as compared with IM or SLPES. SEM, AFM, CLSM and XPS reveal that IM/SLPES can form a denser inhibition film on steel surface through the co-adsorptions of IM and SLPES, which can also well be elucidated by theoretical calculations.

Efficacy evaluation of some bio-insecticides against green leaf hopper (&lt;em&gt;Amrasca biguttula biguttula Ishida&lt;/em&gt;) infesting brinjal

In Bangladesh, brinjal (Solanum melongena L.) is an important vegetable crop due to its year-round cultivation, high demand for consumption, and nutritional value. The main obstacle to the successful cultivation and production of brinjal is insect pests. The current study was carried out in the winter, when green leafhoppers (Amrasca biguttula biguttula), one type of sucking insect pest, are most prevalent. Early in the vegetative stage, an infestation of green leaf hoppers (GLH) was noted; as the canopy size increased, so did their numbers. The consumption of brinjal with its peel poses a health risk due to possible contamination with toxic chemical insecticides. We assess a few non-toxic or minimally toxic bio-insecticides against GLH in order to tackle this crucial problem. Fizimite, one of the bio-insecticides, was found to be effective against GLH in a sodium lauryl ether sulfate preparation. Fizimite decreased the amount of GLH in the plant by 85.8%, the amount of leaf infestation by 77.84%, and the amount of GLH-infected brinjal leaf abundance by 54.34%. But Voliam Flexi, a chemical control, was also discovered to be successful against GLH. Fizimite may therefore be a non-toxic, bio-rational substitute for Voliam Flexi, a synthetic, toxic medication used to control GLH.

Exploring selected bioinsecticides for management of cotton aphids (Aphis gossypii Glover) of brinjal in Bangladesh

Brinjal (Solanum melongena L.) is a popular vegetable in Bangladesh being nutritious, tasty, and cultivable throughout the year. Insect pests are the major constraint to its successful cultivation and production. The present study was conducted during the winter season when the sucking insect pests especially cotton aphids (Aphis gossypii Glover) are most abundant. Aphid infestation was observed in the brinjal plants since the early vegetative stage and sometimes the infestation rate reached up to 100 percent. Moreover, the infestation rate fluctuated with plants or duration. Aphids suck the cell saps resulting in stunting the growth of plants and yield reduction. As brinjal is consumed without peeling, contamination with toxic insecticides is a health concern. To address this, some bioinsecticides including abamectin preparation ‘Biomax M’, sodium lauryl ether sulphate preparation ‘Fizimite’, azadirachtin preparation ‘Fytomax’, Saccharopolyspora spinosa and Bacillus thuringiensis var. Kurstaki broth mixture preparation ‘Spinomax’, and potassium salt of fatty acid preparation ‘Fytoclean’ were selected to combat aphids. Besides, Voliam Flexi was applied as chemical control. A field study showed that abamectin preparation Biomax M was very potent against aphids showing zero percent aphid infestation. In addition, the chemical control Voliam Flexi 300 SC also provided zero percent aphid infestation. Therefore, Biomax M might be the non-toxic alternative to Voliam Flexi 300 SC for controlling aphids.

Study on dynamic characteristics of anionic surfactants containing ethoxy groups wetting bituminous coal

Coal dust restricts coal mine safety and green production. Wet dust removal is widely used in coal mining, processing and transportation. High-efficiency dust suppressants help control coal dust and improve the working environment. The wetting behaviors of dust suppression droplets on coal affect the dust reduction efficiency. In order to select high-quality and efficient water-based materials, four ethoxy-containing surfactants with similar structures, fatty alcohol ether sulfate (AES), lauryl alcohol sulfosuccinate disodium (MES), fatty acid methyl ester ethoxylates (FMEE) and fatty acid methyl esters ethoxylate sodium sulfonate (FMES), are selected to prepare solutions with different concentrations. Through the droplet impact wetting experimental system, the dimensionless spreading coefficient of droplets is compared. The results show that the spreading behavior of the four surfactant-containing droplets is better than that of distilled water droplets, and the maximum dimensionless spreading coefficient follows the rule of AES > MES > FMES > FMEE >distilled water. The maximum dimensionless spreading coefficient of the droplet first increases sharply with the increase of the concentration, and then increases slowly when the concentration reaches the critical micelle concentration (CMC). The adsorption configuration of water-surfactant-coal system is simulated by molecular dynamics (MD) simulation. The relative concentration distribution of each component and the mean square displacement (MSD) of water molecules are analyzed. The interaction energy of the system is calculated. The simulation results verified the effectiveness of the impact wetting experiment results.

Biodegradation of sodium lauryl ether sulfate (SLES) contamination by Pseudomonas aeruginosa isolates

Sodium lauryl ether sulfate (SLES) is a surfactant commonly used in the formulation of detergents, which is typically disposed of in wastewater treatment plants. The current study describes the effectiveness of bacteria isolated from Iraqi wastewater to remove SLES. 16S rRNA genetic analysis revealed that this strain is Pseudomonas aeruginosa. Three temperatures (30, 35, and 40oC) and pH values (5,7, and 9) were chosen for this study, and three concentrations of SLES (25, 50, and 100 mg/L) were used. The SLES anionic surfactant showed that the best biodegradation by Pseudomonas aeruginosa was at a temperature of 30oC and both pH 7 and 9, while the removal percentages for them were 98.44% and 96.36%, respectively, at 25 mg/L of SLES. The outcomes of this study revealed the potential and significance of SLES removal in actual effluents by aerobic biodegradation. The ability of this bacterium to degrade SLES makes the bacterium an important tool for bioremediation.

Effects of residual foaming agent and defoamer on defoaming-flocculation-filterpress characteristics of earth pressure balance shield muck.

Foaming agents as a combination of several components are usually used as soil conditioning during earth pressure balance shield (EPBS) tunnelling. These residues in waste EPBS muck lead to a series of new challenges for in-situ recycling, i.e., foams overflow flocculation tank. This study investigates the effects of residual foaming agent components and defoamers on defoaming-flocculation-filterpress characteristics of EPBS muck using an improved flocculation and filterpress system. Residual foam height (Hf), defoaming ratio (DFR), antifoaming ratio (AFR), total suspended substance (TSS), turbidity, moisture content (MC), and zeta potential (ZP) were selected as characterization indices. The microstructure of filterpress cakes was analyzed using a scanning electron microscope. Results demonstrate that an enhancement within 0.0-1.0wt.% for sodium fatty alcohol polyoxyethylene ether sulfate (AES) and alpha olefin sulfonate (AOS) significantly reduces DFR and AFR. The MC and ZP decline, while the Hf and turbidity enhance. The combinations of nonionic surfactants alkyl polyglycoside (APG) and fatty alcohol-polyoxyethylene ether (AEO) in a concentration range of 0.0-1.0wt.% with 0.2wt.% AES causes the Hf, DFR, AFR, turbidity, and ZP to exhibit absolutely different variations. The MC with the growth in both APG and AEO presents a trend of first decreasing and then increasing. By increasing foam stabilizers sodium carboxymethyl cellulose (CMC) and guar gum (GG) within 0.02-0.10wt.%, the AFR, TSS, and ZP enhance in varying degrees, while the Hf, DFR, and MC gradually reduce. With the increase of defoamers hydroxyl silicone oil-glycerol polyoxypropylene ether (H-G) and dimethyl silicone oil-glycerol polyoxypropylene ether (D-G) within 0.002-0.010wt.%, the DFR and AFR are significantly improved, while the TSS, turbidity, MC, and ZP display varying degrees of reduction. Moreover, defoaming-flocculation-filterpress mechanisms of EPBS muck are explored to provide a useful reference for actual in-situ recycling projects.

Impact of anionic surfactant-based foaming agents on the properties of lightweight foamed concrete

Due to its low density, high thermal insulation, and ability to contribute to energy saving, lightweight foamed concrete (LWFC) is a versatile material that finds use in a wide variety of contexts. The properties of foam are significantly influenced by the selection of surfactant and foam production parameters, which in turn impact the properties of LWFC. Therefore, the anionic foaming agent effect on the distinct properties of LWFC needs to be investigated to create a lightweight structure in modern days. This research aims to better understand the interactions between cement particles and anionic foaming agents, which produce stable and consistent aqueous foams because of their negative charge. Investigations were carried out on the effects of anionic foaming agents of LWFC features on the fresh state characteristics, mechanical behaviour, microstructure, and transport properties. In this investigation, four distinct types of anionic surfactants specifically sodium lauryl sulphate (SLS), alpha olefin sulfonate (AOS), sodium lauryl ether sulphate (SLES), and sodium alcohol ether sulphate (AES) were considered, with all mixes maintaining a consistent cement-to-sand ratio and identical amounts of foaming agents. The fresh state testing exhibits that AOS-based LWFC may be preferred when lower setting time and spreadability, as well as a higher density, are required. The AOS-based LWFC exhibits lower capillary sorption, water absorption, and gas permeability than SLES, SLS, and AES-based LWFC. At 28 days, about 91–96 % of the compressive, tensile, and flexural strength of AOS-based LWFC is obtained for SLS, SLES, and AES-based LWFC. In addition, at the same curing age, the results for modulus of elasticity were over 6 % higher in the AOS-based LWFC mixture than in the other mixes. The pore structural and microstructural behavior revealed that AOS and SLS foamed-based LWFC exhibit a considerable reduction of macropores, or long capillaries, with diameters less than 500 µm, which can be used in the lightweight structure in modern days. This research emphasizes the significance of selecting the appropriate foaming agents to optimize the mechanical and transport properties of LWFC, which provides substantial benefits for contemporary construction practices.

Adsorption behavior and application properties of natural alcohol polyoxyethylene polyoxypropylene ether sulfate

In recent years, the Polyoxypropylene (PO) group has been introduced between the hydrophobic group and the polyoxyethylene (EO) group of traditional surfactants to enhance interfacial properties. However, literature on surfactants introducing PO chains between EO and hydrophilic groups remains scarce. In this study, three variants of natural alcohol polyoxyethylene polyoxypropylene ether sulfate (C1214E3PnS), each with different PO addition numbers, were synthesized from natural alcohol ether through sulfation and neutralization reactions. The adsorption behavior of C1214E3PnS with different PO addition numbers was investigated and compared to AES by measuring surface tension, dynamic surface tension, and contact angle. The results indicate that as the number of PO increases, both the critical micelle concentration and maximum adsorption capacity decrease. Additionally, pC20 and the number of PO groups introduced in the surfactant show a linear negative correlation, indicating a decline in surfactant efficiency. Due to an adsorption barrier, C1214E3PnS is governed by a mixed diffusion-kinetics adsorption mechanism. According to the application performance of C1214E3PnS, as the number of PO increases, wettability and foam stability have decline, while emulsifying performance is significantly enhanced. In conclusion, surfactants such as C1214E3PnS do not favor adsorption at the solid–liquid interface, but enhance the properties at the oil–water interface.

Impact of surfactant polydispersity on the phase and flow behavior in water: the case of Sodium Lauryl Ether Sulfate

This study delves into the impact of molecular polydispersity on the phase behavior of Sodium Lauryl Ether Sulfate (SLES) surfactant, aiming to deepen understanding of its implications for fundamental science and industrial applications. SLE3S is utilized as a model compound: a comprehensive characterization of molecular polydispersity is conducted using Gas Chromatography–Mass Spectrometry and Nuclear Magnetic Resonance spectroscopy, juxtaposing the findings with those for SLE1S.Our comprehensive investigative approach entails: (i) employing Time-Lapse dissolution experiments in microchannel geometries to observe the dissolution and phase transitions; (ii) utilizing polarized light microscopy, confocal microscopy, and Small Angle X-ray Scattering for microstructure identification assessments; (iii) conducting rheological evaluations at various concentrations and temperatures to determine their effects on the surfactant properties.The findings reveal that SLE3S, being more polydisperse, demonstrates complex phase behavior not observed in the less polydisperse SLE1S. Notably, SLE3S exhibits a unique concentration domain, corresponding to a concentration of about 60 %wt, where hexagonal (H), cubic, and lamellar (Lα) phases coexist, resulting in highly viscoelastic heterogeneous mixtures. This behavior is attributed to the local segregation of surfactant components with varying polarity, underscoring the crucial role of molecular polydispersity in the phase behavior of SLES surfactants.

Carbomer Hydrogels with Microencapsulated α-Tocopherol: Focus on the Biocompatibility of the Microcapsules, Topical Application Attributes, and In Vitro Release Study.

The microencapsulation of α-tocopherol based on the complex coacervation of low-molecular-weight chitosan (LMWC) and sodium lauryl ether sulphate (SLES) without harmful crosslinkers can provide biocompatible carriers that protect it from photodegradation and air oxidation. In this study, the influence of the microcapsule wall composition on carrier performance, compatibility with a high-water-content vehicle for topical application, and release of α-tocopherol were investigated. Although the absence of aldehyde crosslinkers decreased the encapsulation efficiency of α-tocopherol (~70%), the variation in the LMWC/SLES mass ratio (2:1 or 1:1) had no significant effect on the moisture content and microcapsule size. The prepared microcapsule-loaded carbomer hydrogels were soft semisolids with pseudoplastic flow behavior. The integrity of microcapsules embedded in the hydrogel was confirmed by light microscopy. The microcapsules reduced the pH, apparent viscosity, and hysteresis area of the hydrogels, while increasing their spreading ability on a flat inert surface and dispersion rate in artificial sweat. The in vitro release of α-tocopherol from crosslinker-free microcapsule-loaded hydrogels was diffusion-controlled. The release profile was influenced by the LMWC/SLES mass ratio, apparent viscosity, type of synthetic membrane, and acceptor medium composition. Better data quality for the model-independent analysis was achieved when a cellulose nitrate membrane and ethyl alcohol 60% w/w as acceptor medium were used.

Effects of surfactant types on anthracite dust wettability: Experimental and molecular simulations

To study the wetting mechanism of surfactants at the solid–liquid interface of anthracite, a combination of experiments and molecular simulation was used to explore the adsorption and wetting processes of four surfactants, namely, fatty alcohol polyoxyethylene ether N = 9 (AEO9), Triton X-100, rapid penetrant T (PRT), and sodium alkyl ether sulfate (AES) on anthracite. The wetting mechanism of surfactants on anthracite was analyzed at both macroscopic and microscopic levels by surface tension, contact angle, settling time, and changes in surface morphology and functional groups on the anthracite surface. The presence of OH-π and C = O was determined to significantly enhance anthracite wettability. The anthracite/surfactant/water system was constructed from a microscopic perspective, and the interaction energies, relative concentration distributions along the Z-axis, diffusion coefficient (D) of water molecules, radial distribution functions (RDF) of hydrophilic groups and water molecules, and coordination numbers of the components were analyzed. The results show that the wetting effect depends on the adsorption state of the surfactant at the anthracite/water interface and the strength of the interaction between the surfactant and water molecules. The addition of surfactants enhances the adsorption thickness of water molecules along the Z-axis and generates more hydrogen bonds, which play a role in fixing water molecules and lead to a decrease in the D of water molecules. RPT forms the highest number of hydrogen bonds with water molecules and has the lowest D of 0.479 × 10-5 cm2/s, indicating strong wetting ability. The RDF of O atoms in surfactants and water molecules shows a similar trend, with two peaks one strong and one weak. The coordination numbers are 1.356, 1.057, 1.003, and 0.903, respectively. The final wettability of the surfactant on the anthracite depends on the synergistic interaction between the oxygen functional groups (OGs) as compared to the coordination number of the individual OGs.