Study on the properties of sodium lauroyl lactate anionic surfactant and cationic surfactant in a mixed system

Adsorption, Aggregation, and Application Properties of Green Pluronic Aliphatic Alcohol Ether Carboxylic Acids and Nonionic/Amphoteric Surfactants in Water

In the realm of colloid and interface science, new types of green surfactants, including anionic Pluronic alcohol ether carboxylate (AEC), branched alkyl glucoside (IG), and zwitterionic coconut oil amide propyl betaine (CAB), have been identified and merit further exploration. AEC, characterized by its inclusion of 5 EO and 3.5 PO units, was synthesized, and its behavior in aqueous solutions with IG and CAB was meticulously examined. Their performance in applications such as foam generation, wetting, and the dispersion and stabilization of graphene was also evaluated. At αAE5P3C = 0.5, AE5P3C/CAB exhibited superior surface and interfacial properties compared to AE5P3C/IG. In these hybrid systems, the self-assembly of micelles is predominantly influenced by hydrogen bonding, electrostatic interactions, and hydrophobic forces. Kinetic analysis further confirmed that the driving force for micelle formation in these hybrid systems is enthalpy, with the adsorption process involving a mixed diffusion-kinetic adsorption mechanism. AE5P3C/CAB demonstrated enhanced foaming ability, foam stability, and wetting properties compared to AE5P3C/IG. Intriguingly, the optimal dispersion and stabilization of graphene were achieved with AE5P3C/IG at αAE5P3C = 0.2, providing a foundational basis for its potential application in graphene-based systems. A thorough examination of the synergistic mechanisms and application potential of these three distinct surfactants in aqueous solutions was presented, taking into account various charged ions and the specific hydrophilic and hydrophobic groups of EO and PO. This study not only provides fundamental insights into their intrinsic properties but also offers a fresh perspective for the ongoing exploration of green surfactants.

Impact of the Hydrophobic Phase on the Interfacial Dilational Rheology of Alkoxy Carboxylate/Cetyltrimethyl Ammonium Chloride Mixtures

Despite extensive investigations on the interfacial activities of mixed anionic and cationic surfactants (Sa/c), the influence of the hydrophobic phase on their interfacial assembly and dilational rheology remains unaddressed. In this study, the interfacial dilational rheology of alkoxy carboxylate (anionic)/cetyltrimethylammonium chloride (cationic) surfactant mixtures was studied at various interfaces. The dilational modulus of Sa/c increases linearly with interfacial pressure at the interfaces of air, n-hexane/n-octane/n-hexadecane, and toluene. The limit elasticity (ε0) is similar at air and alkane interfaces but significantly decreases at the toluene interface. To explain these phenomena, all-atom molecular simulation was carried out to investigate the microscopic features of surfactants at the interface. The findings emphasize the crucial role of anionic/cationic surfactant bound pairs in regulating interfacial rheology. Sa/c tend to form large aggregates at the air/water surface. When mixed with alkanes like octane, most Sa/c remain as ion pairs. However, when toluene is employed, the coordination number between anionic and cationic surfactants sharply decreases due to π-π interactions between the toluene molecules and the phenyl groups in the anionic surfactant. This leads to a much lower interfacial modulus because interactions between oil molecules and surfactants cannot compensate for weakened interactions among anionic/cationic surfactants. These results suggest that Sa/c in this study tolerate alkanes but are not resistant to aromatics, which helps explain why Sa/c demonstrate excellent performance for the chemical enhanced oil recovery of a high-wax reservoir and further provides fundamental knowledge of their potential applications, such as gas well deliquification using foamers in the presence of condensate oil, textiles, etc.

Interaction, Surface Activity, and Application of Mixed Systems of Alcohol Ether Sulfate Anionic Surfactants with Multiple Ethylene Oxide Groups and Gemini Quaternary Ammonium Surfactant

The surface activities and application properties for the mixtures of cationic surfactants tetramethylene-1,4-bis[N,N-bis(hydroxypropyl)-hexa/decyloxypropylammonium] bromide (GC10-P) and tetramethylene-1,4-bis[N,N-bis(hydroxyethyl)-hexa/decyloxypropylammonium] bromide (GC10-E) and anionic surfactant isomeric sodium fatty alcohol ether sulfates (iso-AE9S) were investigated using both the tensiometry and the conductometry. The interaction parameters and thermodynamic micellization parameters of GC10-P/iso-AE9S and GC10-E/iso-AE9S mixtures were evaluated by Clint-Rubingh and Motomura theoretical models. When the mole fraction of α1 for GC10-P/iso-AE9S mixed system was 0.2, the critical micelle concentration (CMC) reached a minimum of 1.61 × 10-4 mol/L, and the minimum critical micelle concentration of the GC10-E/iso-AE9S mixed system is 2.67 × 10-5 mol/L at α1 = 0.6. The CMC value of the mixed system is 1-2 orders of magnitude lower than that of any single component. The results indicate that the synergistic effects of the investigated mixed systems (evaluated by βm) are in order of GC10-P/iso-AE9S < GC10-E/iso-AE9S, with maximum βm values of -17.98 and -9.78, respectively. The change in zeta potential indicates that the poly(ethylene oxide) chain has weakened the charge density of the hydrophilic headgroup of the anionic surfactant. The interfacial tension at the oil-water interface in the mixed system of anionic/cationic surfactants is lower than that of any single component, exhibiting a higher interfacial activity. The mixed system exhibits a decreased contact angle and superior wetting ability over any single component, and it also enhances foam performance, emulsification performance, and degreasing performance.

Binary mixture of ionic liquid and span 80 for oil spill remediation: Synthesis and performance evaluation

The synthesis of new surfactants helps to mitigate the environmental and financial effects of oil spills by providing efficient cleanup options. Herein, this study provides the development of a binary mixture of Span 80 and Choline myristate [Cho][Mys], a surface-active ionic liquid (SAIL) as green dispersant for oil spill remediation. The synergistic interaction at a 60:40 (w/w) ratio significantly lowered the critical micelle concentration (cmc) to 0.029 mM. Dispersion efficiency tests with Arab crude oil showed optimal performance at a 60:40 ratio of Span 80 and [Cho][Mys] (1:25 dispersant to oil ratio, v/v), achieving 81.16 % dispersion effectiveness in the baffled flask test. The binary mixture demonstrated superior emulsion stability (6 h) and the lowest interfacial tension (1.12 mN/m). Acute toxicity experiments revealed the dispersant's practical non-toxicity with an LC50 value of 600 mg/L. Overall, this environmentally benign surfactant combination shows promise as a safe and effective oil spill dispersant.

Fluorescent and visual sensing of sodium dodecylbenzene sulfonate with an aminosilane self-condensation promoting and electrostatic attraction effect-based ratiometric probe

BACKGROUND

Increasing attention has been paid to sodium dodecylbenzene sulfonate (SDBS) detection because it could cause damage to human body and environmental water. For example, SDBS must not be detected on tableware surface according to national standard of China (GB 14934-2016). However, there is no report heretofore addressing SDBS sensing on surfaces. More importantly, the interferents often affect the sensing performance of analytical approaches. Hence, there is an urgent need to establish a method with good anti-interference ability for SDBS detection both on tableware surfaces and in water.

RESULTS

Inspired by a finding that SDBS could cause the generation of white turbidity in (3-aminopropyl)trimethoxysilane (APTMS, an aminosilane) aqueous solution, APTMS modified Mn doped ZnS quantum dots (QDs) and fluorescent (FL) whitening agent (FWA) were constructed as a ratiometric probe for FL and visual sensing of SDBS. The modified QDs aggregated and settled in presence of SDBS, which was likely to be connected to the stimulatory effect of SDBS on the APTMS self-condensation and the electrostatic attraction. The FL emission from the QDs at 605 nm then decreased dramatically, whereas that at 425 nm was virtually constant owing to FWA. SDBS sensing could be achieved by calculating the ratio change of their FL intensities. The detection limits of FL and visual methods were found to be 0.011 and 10 μg/L, respectively, making it one of the most sensitive approaches in literature. Finally, it was successfully utilized for SDBS detection on tableware surfaces and in water.

SIGNIFICANCE

Herein, the specific interaction between SDBS and APTMS was reported and the reaction mechanisms were explored for the first time. The proposed probe based on the effect described above provided a promising potential for SDBS analysis owing to high sensitivity, selectivity, anti-interference ability, and stability (in 20 days).

Unraveling Membrane-Disruptive Properties of Sodium Lauroyl Lactylate and Its Hydrolytic Products: A QCM-D and EIS Study

Membrane-disrupting lactylates are an important class of surfactant molecules that are esterified adducts of fatty acid and lactic acid and possess industrially attractive properties, such as high antimicrobial potency and hydrophilicity. Compared with antimicrobial lipids such as free fatty acids and monoglycerides, the membrane-disruptive properties of lactylates have been scarcely investigated from a biophysical perspective, and addressing this gap is important to build a molecular-level understanding of how lactylates work. Herein, using the quartz crystal microbalance-dissipation (QCM-D) and electrochemical impedance spectroscopy (EIS) techniques, we investigated the real-time, membrane-disruptive interactions between sodium lauroyl lactylate (SLL)-a promising lactylate with a 12-carbon-long, saturated hydrocarbon chain-and supported lipid bilayer (SLB) and tethered bilayer lipid membrane (tBLM) platforms. For comparison, hydrolytic products of SLL that may be generated in biological environments, i.e., lauric acid (LA) and lactic acid (LacA), were also tested individually and as a mixture, along with a structurally related surfactant (sodium dodecyl sulfate, SDS). While SLL, LA, and SDS all had equivalent chain properties and critical micelle concentration (CMC) values, our findings reveal that SLL exhibits distinct membrane-disruptive properties that lie in between the rapid, complete solubilizing activity of SDS and the more modest disruptive properties of LA. Interestingly, the hydrolytic products of SLL, i.e., the LA + LacA mixture, induced a greater degree of transient, reversible membrane morphological changes but ultimately less permanent membrane disruption than SLL. These molecular-level insights support that careful tuning of antimicrobial lipid headgroup properties can modulate the spectrum of membrane-disruptive interactions, offering a pathway to design surfactants with tailored biodegradation profiles and reinforcing that SLL has attractive biophysical merits as a membrane-disrupting antimicrobial drug candidate.

Study on the Properties of the Sodium Lauroyl Glycinate and Sodium Lauroyl Lactylate Composite System

The scientific community has shown a great deal of interest in sodium lauroyl glycine (SLG) and sodium lauroyl lactylate (SLL), two sustainable and eco-friendly substances that are considered as potential bio-friendly alternatives for petrochemical-based amphiphiles. In the present work, the formation of mixed micelle for SLG and SLL surfactant in water was investigated. Meanwhile, the surface interaction and thermodynamic parameters were calculated according to the surface tension curves. The results indicated that at certain ratios, SLG/SLL surfactant mixtures had synergistic effects that could yield higher surface activity and improve application performance. When the mole fraction of SLL (α_SLL) was 0.4, γ_cmc achieved a minimum of 22.6 mN m^-1 and displayed the best foaming properties. The mixed solution exhibited the best wetting ability when α_SLL was 0.6. While α_SLL was 0.8, the mixed solution showed the optimum dynamic adsorption properties. And it was found that the antibacterial property of SLG and SLL could be partially preserved after compounding. These results demonstrated for the first time that the mixed environmentally friendly surfactant SLG and SLL has a promising prospect for use in the personal care, detergent, and cosmetic industries.

A Review on Interactions between Amino Acids and Surfactants as Well as Their Impact on Corrosion Inhibition

Amino acid-surfactant interactions are central to numerous studies because of their increased effectiveness in chemical, biological, household and industrial use. This review will focus on the impact and effect of the physicochemical properties, temperature, pH, and surfactant chain length of the amino acid for detailed exploration of amino acids and surfactants in aqueous medium. The impact of cosolvent on self-aggregation, critical micelle concentration (CMC), and binding affinity with other biomolecules, as well as amino acid-surfactant interactions, are the epicenters. The results show that increasing the temperature causes negative enthalpy for ionic surfactants and micellization, implying that micellization and amino acids are thermodynamically spontaneous and exothermic, accompanied by positive entropy. As these physicochemical studies are additive, the amino acid and ionic surfactant interactions provide clues on protein unfolding and denaturation under different media, which further changes with a change in physiological conditions like pH, cosolvent, chain length, and temperature. On varying the pH, the net charge of the amino acid also changes and, subsequently, the binding efficiency of the amino acids to the surfactants. The presence of cosolvent causes a lowering in the hydrophobic chain, which changes the surfactant's CMC. At a reduced CMC, the hydrophobic characteristic of amino acid-surfactant associations is amplified, leading to rapid denaturation of proteins that act as propulsion under the influence of extended chain surfactants. Amino acids are one of the most intriguing classes of chemicals that produce high inhibitory efficacy. Amino acids are also a component of proteins and therefore, found in a significant part of the human body, further making them a promising candidate as corrosion inhibitors. In this review article, authors have also focused on the collection and investigation for application of amino acid-surfactant interactions in corrosion inhibition. Various predictive studies/in silico studies are also reported by many research groups, such as density functional theory (DFT) calculations and molecular dynamics simulations to obtain tentative electronic, structural, and physiochemical characteristics like energies of the highest occupied molecular orbitals and lowest unoccupied molecular orbitals, binding energy, Gibb's free energy, electronegativity, polarizability, and entropy. In silico studies are helpful for the mechanism predictions of the process occurring on metal surfaces.

Synergism and properties of binary mixtures based on an arginine dodecyl ester surfactant

The properties of binary mixtures of new cationic amino acid surfactant arginine dihydrochloride dodecyl ester (ADDE) with alkyl poly glycosides (APGs) were studied systematically by evaluating surface tension, conductivity, dynamic...