Journal of Surfactants and Detergents最新文献

This study investigated the properties, namely: surface tension, foam, emulsion, and cloud point of a library of bio-based surfactants (represented as C_nEO_m where C is hydrophobic carbon chain and EO is ethylene oxide). The surfactants were derived from ring-opening alkyl oleate epoxides with polyethylene glycol (PEG) and monomethyl polyethylene glycol (MPEG) of varying chain lengths. Surfactants demonstrated good surface properties having surface tension at critical micelle concentration (CMC) between 35 and 38 mN/m, and recorded CMC values far lower than what was reported for most commercial ethoxylated surfactants. Foamability increased with over 30% foam increase upon increasing agitation speed from 6000 to 11,000 rpm. Branching, hydrophobic carbon chain length, and PEG chain length were seen to impact foamability and foam stability. Foam properties exhibited by the surfactants were found to be superior to those demonstrated by some known commercial nonionic surfactants. Emulsions formed by the oleate ester surfactants were stable over several weeks after formation. Surfactants showed high cloud points, which increased with increasing number of ethylene oxide units. However, the addition of co-solutes depressed the cloud point in the order Na₂SO₄ > NaCl > NaNO₂.

Solubilization of oil-soluble substances in aqueous solution is essential in daily chemistry. Commonly used synthetic solubilizers are environmentally harmful and have limited applications. In this study, sophorolipid, a biosurfactant, was purified through an efficient, simple, and solubilization-compatible method, yielding an aqueous acidic sophorolipid (acid-SL) with high purity of 96 wt%. The bola structure of acid-SL conferred reversible pH-responsive micelle behavior and therefore a distinctive solubilization effect on polar small molecules under neutral pH environment. Based on this, the synergistic solubilization effect of acid-SL in combination with rhamnolipid (RL) was confirmed, with the optimal compound ratio being acid-SL/RL = 0.95:0.05. The compound system significantly improved the solubilization ability under acidic conditions and had superior solubilization capacity for oil-soluble substances such as essential oils, fragrances, and preservatives compared to commonly used solubilizers like Polysorbate 20 and Polyoxyethylene 40.

This study evaluated the ecotoxicological effects of sophorolipids (SLs), biosurfactants with potential environmental applications, on the aquatic plant Spirodela polyrhiza (duckweed). Key growth indicators, including biomass, foliose thalli, and leaf area, were examined under varying SL concentrations. Results indicated that low to moderate SL concentrations (below 100 mg/L) had minimal adverse effects on duckweed growth, whereas higher concentrations (200–300 mg/L) significantly inhibited growth and triggered stress responses. Morphological and physiological assessments revealed that elevated SL concentrations caused substantial frond wilting, root hair damage, and reductions in photosynthetic pigments. Antioxidant responses, such as glutathione (GSH), malondialdehyde (MDA), and catalase (CAT) enzyme activities, increased adaptively at low to moderate SL concentrations but declined at higher levels, indicating severe oxidative stress. Despite these adverse effects, S. polyrhiza exhibited a remarkable ability to degrade SLs even at high concentrations, demonstrating the exceptional biodegradability of SLs. Overall, the findings emphasize the relative safety of SLs at low to moderate concentrations in aquatic environments, underscoring their potential as environmentally friendly surfactants when used responsibly.

The utility of bicontinuous microemulsions (BMEs) as carriers of the antimicrobial peptide (AMP) gramicidin D and antiseptic chlorhexidine was investigated for possible topical delivery to chronic wounds. The two water-insoluble solutes dissolved in pre-formed one-phase BMEs of Water/Polysorbate 80/Limonene/Ethanol/Glycerol and Water/Aerosol-OT (AOT)/Polysorbate 85/Isopropyl Myristate and an AOT/Polysorbate 85 Winsor-III system, achieving gramicidin and chlorhexidine concentrations of 1.0 wt% and 0.5% individually and 0.5% and 0.3% in mixtures at 22°C, respectively. Small-angle neutron scattering measurements demonstrated that both solutes decreased surfactant interfacial activity and increased interfacial fluidity for the Polysorbate 80 system. For the AOT/Polysorbate 85 systems, ellipsoidal aggregates consisting of gramicidin and likely adsorbed surfactant and oil formed, while chlorhexidine enhanced the surface activity of surfactants. According to bioassays performed on artificial skin, the incorporation of melittin, gramicidin, and chlorhexidine in general enhanced the bioactivity of Polysorbate 80 BMEs for 24 h treatment against relevant antibiotic-resistant bacteria found on skin relative to controls. Yet, BME treatments were less effective than aqueous melittin control, in contrast to well diffusion bioassays performed previously. The results reflect the strong impact of AMPs and antiseptics on BME structure and dynamics and the complexity of formulating BMEs for optimal antimicrobial activity.

In this short communication, the role of sodium hypochlorite as a salt in a surfactant-oil–water system is explored through calculations of the hydrophilic–lipophilic difference model. The effect of hypochlorite salt on hydrophilic–lipophilic difference (HLD) is mathematically calculated for anionic (sodium linear alkylbenzene sulfonate, sodium lauryl sulfate, and sodium cocoate) and a zwitterionic surfactant (cocoamidopropyl betaine) having different surfactant parameters (sometimes referred to as characteristic curvatures). Model systems typical of hypochlorite cleaning products showed negative HLD values for lipid soils, but near zero for essential oil components and other low-equivalent alkane carbon number oils.

This experimental study examines the effect of different surfactants—sodium lauryl sulfate (SLS), sodium dodecyl sulfate (SDS), and bio-surfactant rhamnolipids (RHL)—on the viscosity of distilled water (DW) with varying concentrations of aluminium oxide (Al₂O₃) nanoparticles (NPs). Al₂O₃ NPs were used in concentrations ranging from 0.02 to 0.5 wt%, while surfactant concentrations ranged from 2000 to 4000 ppm for SDS and SLS and from 200 to 600 ppm for RHL. Viscometric experiments revealed that the type and concentration of surfactants, along with the NP loading, influenced the viscosity of nanofluids (NFs). NFs without surfactant exhibited consistently higher viscosities compared with DW with surfactant alone. At 0.5 wt% Al₂O₃, NF viscosity was 17% higher than SDS and RHL and 9% higher than SLS. Interestingly, in DW with both surfactant and NPs, viscosity initially decreased with increasing Al₂O₃ concentration, followed by a rapid increase after 0.1 wt%. These results offer insights into the interaction between surfactants and NPs, relevant for industries requiring precise viscosity control, such as pharmaceuticals, cosmetics, and environmental applications.

The hydrophilic–lipophilic difference (HLD) equation is being used extensively for designing oil-in-water based surfactant systems to maximize oil solubility and minimize oil–water interfacial tension. However, the equation was developed for and almost always presumes that the salt is sodium chloride. The work described in this paper extends the equation to other monovalent cations (Li, K) and divalent anions (CO₃). The equation was adjusted for molecular weight and the number of cations in the salt. For anionic surfactants, the Hofmeister series successfully qualitatively predicts that the salt concentration to reach HLD = 0 scales with Li > Na > K, that is, the surfactant with lithium requires more salt for the water to reach the hydrophobicity required. Although the exact salt concentration depends on the anionic surfactant headgroup, the difference in optimal salinity between two cations appears to not be dependent on headgroup. Also, CO₃ reduces the activity of the cation as compared to Cl. For narrow-range alcohol ethoxylates, there is little difference between Na and K; while Li requires more salt for a given increase in hydrocarbon number of carbons to reach HLD = 0. A broad-range ethoxylate gives inconsistent results, which we attribute to the finite solubility of some surfactant components in the oil.

Researchers are mainly suggesting that optimizing the heat efficiency of thermal apparatus by dispersing nanoparticles into the foundation fluid will boost its heat efficiency in boiling sectors. Many investigators conduct research on factors such as fluid properties, bubble growth and bubble dynamics, heater surface effect, and so forth. However, the problem of deficiency in stability created by nanoparticle sedimentation or agglomeration into the base fluid over time has restricted practicable applications, which has drawn considerable attention in recent years. To overcome that, many researchers used a common technique, the addition of stabilizing agents like surfactants/additives into the nanofluids (NFs) to achieve stability. Understanding the behavior of surfactants in NFs and their effect on various important physical properties of the working fluid is required. In this review, firstly discuss the impact of adding surfactants on the stability of an aqueous solution. Additionally, it provides a concise assessment of how the inclusion of surfactants affects different thermal physical characteristics like interfacial tension, viscosity, and thermal conductivity of aqueous solutions or NFs. Finally, it outlines the primary obstacles and challenges encountered by researchers that continue to be areas of focus for future investigations concerning NFs containing surfactants.

Surfactant–oil–water (SOW) systems, particularly when packaged in metal containers, require chemical reagents with preservative and anticorrosive properties. This study aims to investigate the influence of sodium benzoate (NaBz) on fundamental interfacial properties of the surfactant lauryl ether sulfate (SLES) with two ethoxylation units (EO = 2). Using a combination of surface tension, electrical conductivity, and isothermal titration calorimetry (ITC) measurements, we evaluated SLES systems in the presence of NaCl, NaBz, and various mixtures of these salts using salinity scans, at room temperature. NaBz inhibits the formation of triphasic system in SOW formulation. The thermodynamic stability of SLES micelles followed the order: $�{�∆�G�}_{�\mathrm{mic}�,�\text{NaCl}�}^0�<�{�∆�G�}_{�\mathrm{mic}�,�\text{NaBz}�}^0�~�{�∆�G�}_{�\mathrm{mic}�,�1�:�1�}^0�<�{�∆�G�}_{�\mathrm{mic}�,�H_2�O�}^0$ with entropy being the primary driving force. The results suggest that NaBz acts as a potential interfacial structure decoupler. This novel behavior of NaBz may have important implications for its use in SOW systems, particularly in formulations requiring stability and integrity in aggregation state.

The laundering process is an essential routine for maintaining the cleanliness and freshness of textiles. Achieving an efficient deposition and retention of fragrances on different fabric types remains a complex challenge. This study provides a novel comparison of the impact on perfume deposition of different fabric types across wash cycle stages and wash conditions. The critical role of perfume redeposition during rinsing is examined, where micelles entrapped in the textile matrix break due to surfactant concentrations dropping below the critical micelle concentration (CMC), resulting in the release and subsequent redeposition on fabrics of perfume raw materials (PRMs) contained in the micelles. Our findings reveal that adsorption kinetics are faster on cotton compared with polyester. Cotton, due to its amphoteric nature, exhibits greater interaction with water molecules during rinsing, leading to more significant PRM loss. Conversely, polyester demonstrates a higher PRM retention capacity, which can be attributed to its hydrophobic nature. Surprisingly, however, we find that redeposition during the rinse steps of hydrophobic PRMs is more pronounced on cotton than polyester, which may be due to their respective water retention capacities and consequent effect on the micelle breaking mechanism.