Journal of Surfactants and Detergents最新文献

Biosurfactants represent a promising choice for the development of environmentally friendly and gentle personal care cleansers. Building viscosity is one of the major challenges to apply biosurfactants. In this study, sodium lauroyl sarcosinate (LS) and sodium lauroamphoacetate (LA) were used as bases to build wormlike micelles, and subsequently rhamnolipids were introduced to build mild surfactant systems. The LS-LA mixture had the highest viscosity at the mass ratio of 1:5 and pH 6.0. After adding 1 wt% and less rhamnolipid, relatively high viscosity can be maintained. The viscosity of LS-LA-rhamnolipid can be increased by adding NaCl and more significantly by the addition of carrageenan due to its synergistic interactions with the surfactant mixture. In addition, the foaming properties of the systems are characterized with different amounts of rhamnolipid and carrageenan, which are correlated with the bulk viscosity and interfacial elasticity of the diluted solution used for the foaming test. Rhamnolipids have both high mildness and cleaning efficacy and adding rhamnolipids can significantly increase the mildness of the system. This study offers practical solutions for the incorporation of rhamnolipids or other biosurfactants in the formulation of personal care cleansers.

Glycolipids produced and secreted by oleaginous yeasts are renewable compounds with important physico-chemical properties, and multiple biological and industrial applications. The large-scale production of these compounds has been limited by high production costs and low yields. The sophorolipid-producing yeast Pseudohyphozyma bogoriensis may possess the ability to grow in fermentation systems using carbon substrates deriving from inexpensive lignocellulosic biomass, while simultaneously secreting high value biomaterials. In this study, comparative analyses between different cellulose-derived carbon sources including glucose, cellobiose, and sodium carboxymethyl cellulose confirmed the ability of P. bogoriensis to grow and accumulate glycolipids using these substrates. On a dry weight basis, the highest yields of about 4% (wt/wt) glycolipids were obtained when cellobiose was supplemented at 10 g/L in shake-flask fermentations. When the unconventional carbon substrate sodium carboxymethyl cellulose was supplemented, cultures exhibited a lower glycolipid yield of 0.3% (wt/wt), but the dry weight was higher compared to other substrates. Analytical analyses using various chromatography methods confirmed the chemical profiles, whereas both monoacetylated and diacetylated sophorolipid forms with 22 carbon long-chain hydroxy fatty acid were identified in all glycolipid extracts. Surface tension (ST) and critical micelle concentration (CMC) measurements showed that glycolipids produced on cellulose-derived substrates exhibited similar or even superior physical properties compared with glucose. Furthermore, availability of the yeast genome sequences facilitated the identification of putative genes that may be involved in cellulose hydrolysis (e.g., cellulase-like). Information on genomic and metabolic pathways is a prerequisite for trait improvement toward increasing the production of high value biomaterials.

Green surfactants produced from peptides and their derivatives have excellent surface chemistry and application properties. A mild, biocompatible, and rapidly biodegradable green surfactant, potassium N-lauroyl wheat peptide (PLW), was synthesized by an acylation method in the aqueous phase with lauryl chloride and wheat oligopeptide as starting materials. Furthermore, the isoelectric point, equilibrium surface tension, dynamic surface tension, micellar aggregation behavior, foaming, and irritating properties of PLW were studied. Wheat oligopeptides were discovered to have the greatest glutamic acid content, accounting for 30.92% of the overall amino acid composition. The findings revealed that the protonation and ionization behavior of PLW was pH dependent. At pH 8.5, water's surface tension was lowered to 32.1 mN/m⁻¹. At high concentrations and pH, PLW formed large aggregates in solution, causing the adsorption behavior of PLW molecules to shift from diffusion-controlled adsorption to mixed kinetic adsorption, with PLW exhibiting great surface activity. Furthermore, PLW has good foaming properties and is non-irritating. As a result, PLW is predicted to become widely employed in the field of household chemicals.

Enhanced oil recovery (EOR) by surfactant flooding has been attractive. Among the surfactants developed alcohol polyoxypropylene (PO)-polyoxyethylene (EO) ether sulfates (APES), also named extended surfactants, have been proved efficient. However, the arrangement of the PO and EO chains as well as the hydrocarbon structure in the molecules may significantly affect their performances. In this paper three APES, C₁₈₋₁₆PO₂₅EO₁₀SO₄Na (I), C₁₈₋₁₆(PO/EO)₂₅₊₁₀SO₄Na (II), and C₁₆GA(PO/EO)₂₅₊₁₀SO₄Na (III) were prepared and investigated, in which APES (I) and APES (II) were designed to have same PO and EO numbers but block and randomly copolymerized respectively with linear C₁₈₋₁₆ fatty alcohols as starting agent, whereas the APES (III) was derived from double chain C₁₆ Guerbet alcohol (C₁₆GA) with PO and EO randomly copolymerized. The results show that the block copolymerized APES (I) gives much better brine solubility and counterion tolerance than the randomly copolymerized APES (II) and (III). Although all APES synthesized are highly surface-active and can reduce Daqing crude oil/simulated brine interfacial tension (IFT) to ultralow by mixing with more hydrophobic surfactants in presence or absence of alkali, the APES (III) gives the lowest IFT due to with double hydrocarbon chains. In addition, it is found that for APES (I) gelation occurs in neutralization process and the corresponding nonionic intermediate is highly viscous, whereas the randomly copolymerized two intermediates are liquid-like with low viscosity, which may be feasible to apply SO₃/air falling film sulfation. This study provided useful information for arrangement of embedded nonionic moiety and hydrocarbon structure in designing extended surfactants for EOR.

Surface pressure (π)–molecular area (A) isotherms were gathered to characterize the packing of binary mixed Langmuir monolayers of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and one of two Gemini surfactants (GS), N,N-bis(dimethyloctadecyl)-1,7-nonanediammonium dibromide (18-7-18) or 1,9-bis(octadecyl)-1,1,9,9-tetramethyl-5-amino-1,9-nonanediammonium dibromide (18-7NH-18) of varying molar fractions. Information about miscibility behavior was derived from the π–A curves by examining the excess free energy of mixing (ΔG_exc) that was calculated through the surface area additivity rule. Surface compressibility modulus (C_s⁻¹) was also used to characterize intermolecular interactions. Mutual interactions between GS and DOPE were analyzed in terms of excess Gibbs energy of mixing and the value of this parameter depended strongly on the composition of the mixed film. GS and DOPE are generally miscible as DOPE reduces intermolecular repulsion between highly charged GS molecules leading to the formation of more densely packed mixed monolayers. However, GS and DOPE are immiscible in equimolar mixtures due to tail group packing mismatch between saturated and unsaturated alkyl chains. The prevalence of attractive synergistic interactions in the monolayers studied differs from a previous finding of antagonistic mixing behavior in GS/DOPE micelles. These results contribute to the understanding of GS-lipid interactions and packing that are critical to the in vitro and in vivo stability of liposomes composed of these molecules used for non-viral gene therapy applications.

The mixed system of sodium cocoyl glycinate and sodium hyaluronate (HA) with different mass concentrations and relative molecular weights was investigated by the surface tension method. All the curves of surface tension versus logarithm of concentration (γ-lgc curves) of sodium cocoyl glycinate-HA mixed system displayed the properties of double platform. The critical micelle concentration (cmc) of sodium cocoyl glycinate was 1.690 g/L at 25°C. The two inflection points of the γ-lgc curves corresponding to the cocoyl glycine-HA mixed system were cac (the critical aggregation concentration) and cmc_e (the extended cmc of sodium cocoyl glycinate), and cac < cmc_e < cmc. With the change of the mass concentration and relative molecular weight of HA, the cac values were almost constant. However, cmc_e increased with the increase of the mass concentration of HA at the same HA molecular weight. For the HA of molecular weight of 800 and 260000 Da, the mass concentration of HA increased from 0.05 to 0.4 g/L, and the cmc_e value increased from 1.199 to 1.390 g/L and 1.102 to 1.330 g/L, respectively. When the mass concentration of HA remained the same, the change in the relative molecular weight of HA had little effect on the cmc_e value. For the mixed system of sodium cocoyl glycine −0.1 g/L HA, when the concentration of NaCl was 2 g/L, the salt enhancement effect was dominant. When the concentration of NaCl was 4 to 8 g/L, the salt weakening effect was dominant. It is indicated that HA can improve the chemical properties of sodium cocoyl glycinate at a certain concentration, thus improving the cleaning, foaming, and foam stability of sodium cocoyl glycinate.

In this brief review, we have discussed various physical chemical principles that guide the functions of surfactants in solution. The surfactants have special functions at the air/liquid and air/solid interfaces forming Gibbs and Langmuir monomolecular films by way of spreading at the interfaces. Their self-aggregation or micelle formation, a remarkable and useful phenomenon has been presented and elaborated. The application of fundamental physical chemistry principles for the understanding of the energetics of the micelle formation has been discussed. The involvement of surfactants in the formation of soft assembled (condensed) matters namely, vesicles, emulsions, foams, reverse micelles (or, microemulsions), gels, and so forth has been presented. The uniqueness of the “critical micelle concentration” (CMC), and its determination have been briefly presented. Applications of surfactants are numerous. We have briefly cited several applications namely, nano-material synthesis, detergency, agrochemical formulations, drug delivery, retardation of water evaporation, and so forth. A short account of bio-related surfactants namely, lung surfactants, bile salts, plant-and microbe-generated bio-surfactants, and their utilities have been also presented.

The use of softeners is essential for enhancing laundered fabrics and hair textures after washing. For these, products based on double-tailed cationic surfactants are used to reduce friction and static electricity, resulting in softer and smoother fibers. These surfactants form lamellar phases in water, which can be turned into vesicles and other bilayer aggregates upon shearing, greatly impacting on the rheological properties of these formulations. This study aims at elucidating how some parameters of the formulation process impact bilayer structures formation and the product rheology, using di(hydrogenated tallow)dimethylammonium chloride (DHTDMAC) aqueous dispersions as model system. Small angle X-ray scattering (SAXS) analyses revealed lamellar phases starting from 3% DHTDMAC, with a bilayer thickness of 1.90 ± 0.03 nm, indicating significant carbon chain interdigitation. At this concentration (3%), bilayers exhibited a repetition distance of 69 nm, unveiling a behavior close to the one predicted for infinite swelling, in which lamellar structures persisted even at high dilution. Temperature plays a significant role in the rheological behavior, with elevated temperatures favoring vesicle formation, resulting in reduced apparent viscosity due to lower resistance of vesicles to flow. Upon heating, differential scanning calorimetry (DSC) analyses revealed a transition from L_β (gel) to L_α (fluid) structures between 28 and 41°C, which was further confirmed by X-ray diffraction (XRD). Both structural and thermotropic features observed were discussed and compared to information reported for a high-purity grade homologue of DHTDMAC, dioctadecyldimethylammonium chloride (DODAC) mixed with water. These findings deepen the understanding of fabric softener formulation and the impact of bilayer structures formation on their properties, and should be used to optimize new formulations, enhancing their overall performance and sensorial quality.

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

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