Sugar-based Surfactants Research Articles

Impacts of hydrophobic chain length on foam stability and CO2 geo-sequestration capacity of sugar-based nonionic surfactants: Molecular dynamics simulation and laboratory experiments

This study investigates the micro-mechanism by which the hydrophobic chain length LHC of alkyl polyglycosides (APGs) affects the stability of CO2 foams, and its influence on the behavior of CO2 sequestration in deep saline aquifers. The results demonstrated that increasing LHC within a specific range (9−11) resulted in enhanced adsorption of APG molecules within the bubble liquid film, augmented binding effect of APG on CO2 and water molecules, and improved cation aggregation at the hydrophilic group of APG, thus strengthening the CO2 foam stability. Nevertheless, further LHC increases weakened the water-solubility of APG, and reduced the aggregation of water molecules and cations around the hydrophilic groups of APG molecules, which weakened the mechanical strength of CO2 foam liquid film and its stability. Low-field nuclear magnetic resonance (NMR) showed that as the LHC increased from 9 to 11, the stability of CO2 foam inside the sandstone core is continuously strengthened, and an ideal piston-like displacement formed. Foam not only improved the CO2 storage space in macro-pores, but also enhanced the entrances and displacements of the internal water in the meso- and micro-pores, providing more space for CO2 sequestration. However, further LHC increases weakened the CO2 foam stability inside the sandstone core. Although CO2 foam could occupy many macro-pores, its ability to divert to meso- and micro-pores was weakened, and the CO2 storage capacity in sandstone cores was reduced overall.

Efficient Demulsification of Crude Oil Emulsion Using Novel Sugar-based Surfactant.

This study aimed to synthesize ecofriendly and low-cost surfactant-based sugar, HA-ST, under mild conditions and a short route via an opening ring of hexadecylsuccinic anhydride (HA) using starch (ST). HA-ST's chemical structure, thermal behavior, and surface activity were evaluated using Fourier Transform Infrared (FTIR) spectroscopy, thermogravimetric analysis, and a pendant drop technique. The results indicated HA-ST formation, thermal stability, and surface activity. HA-ST's green character, low cost, and surface activity recommended its use as a demulsifier for crude oil emulsions at different affecting parameters such as temperature, seawater ratio (SR), demulsifier concentration, demulsification time (DT), and pH. HA-ST demulsification efficiency (DE) was evaluated and compared with a commercial demulsifier (CD). The results showed improved HA-ST's DE with rising temperature, SR, demulsifier concentration, DT, and pH. The DE of HAST reached 100% at 50% of SR and 250 ppm of demulsifier concentration; the same results were obtained using CD. In contrast, HA-ST gave relatively lower DE at low SR (10%) with a value of 70% than the obtained using CD with a value of 75%. The green character, low cost, and DE of HA-ST make it suitable for demulsifying crude oil emulsions, especially those containing more than 30% seawater, compared with CD, which commonly contains two or more traditional surfactants.

Phase behavior and rheology of the sucrose laurate/sorbitan mono-laurate (Span 20)/water pseudo-ternary system

In order to develop a lamellar liquid crystal system consisting of temperature-insensitive and mild non-ionic surfactants, we construct the phase diagram of sucrose laurate (L1695)/sorbitan monolaurate (Span 20)/water pseudo-ternary systems at 25 ℃ based on the direct visual inspection and polarized microscopy. In contrast to the phase diagrams of polyoxyethylene alkyl ethers and co-surfactant mixtures reported in relevant studies, the single-phase region of the liquid crystalline phase in sucrose laurate (L1695)/sorbitan monolaurate (Span 20)/water pseudo-ternary systems is shown to be narrower. Moreover, the liquid crystal phase behaviors of the sucrose laurate/sorbitan mono-laurate (Span 20)/water pseudo-ternary systems are examined in depth applying cryo-SEM, X-ray scattering measurements, rheological test and low field NMR experiments. In the abovementioned aqueous systems with a L1695 to Span 20 mass ratio (between 53.9: 46.1 and 43.3:56.7), sucrose mono-laurate combines with a certain number of sorbitan monolaurate molecules to form a single lamellar liquid crystalline phase. Furthermore, the present experimental results as well as their analysis could give the quantitative playground for the interaction between sugar-based surfactants in aqueous system, which has rarely been investigated compared with the phase behavior of polyoxyethylene alkyl ethers in aqueous solution.

Predicting the Temperature Dependence of Surfactant CMCs Using Graph Neural Networks.

The critical micelle concentration (CMC) of surfactant molecules is an essential property for surfactant applications in the industry. Recently, classical quantitative structure-property relationship (QSPR) and graph neural networks (GNNs), a deep learning technique, have been successfully applied to predict the CMC of surfactants at room temperature. However, these models have not yet considered the temperature dependence of the CMC, which is highly relevant to practical applications. We herein develop a GNN model for the temperature-dependent CMC prediction of surfactants. We collected about 1400 data points from public sources for all surfactant classes, i.e., ionic, nonionic, and zwitterionic, at multiple temperatures. We test the predictive quality of the model for the following scenarios: (i) when CMC data for surfactants are present in the training of the model in at least one different temperature and (ii) CMC data for surfactants are not present in the training, i.e., generalizing to unseen surfactants. In both test scenarios, our model exhibits a high predictive performance of R2 ≥ 0.95 on test data. We also find that the model performance varies with the surfactant class. Finally, we evaluate the model for sugar-based surfactants with complex molecular structures, as these represent a more sustainable alternative to synthetic surfactants and are therefore of great interest for future applications in the personal and home care industries.

Sugar-Based Surfactants: Effects of Structural Features on the Physicochemical Properties of Sugar Esters and Their Comparison to Commercial Octyl Glycosides.

Two series of sugar esters with alkyl chain lengths varying from 5 to 12 carbon atoms, and with a head group consisting of glucose or galactose moieties, were synthesized. Equilibrium surface tension isotherms were measured, yielding critical micellar concentration (CMC) surface tensions at CMC (γcmc) and minimum areas at the air-water interface (Amin). In addition, Krafft temperatures (Tks) were measured to characterize the ability of molecules to dissolve in water, which is essential in numerous applications. As a comparison to widely used commercial sugar-based surfactants, those measurements were also carried out for four octyl d-glycosides. Impacts of the linkages between polar and lipophilic moieties, alkyl chain lengths, and the nature of the sugar head group on the measured properties were highlighted. Higher Tk and, thus, lower dissolution ability, were found for methyl 6-O-acyl-d-glucopyranosides. CMC and γcmc decreased with the alkyl chain lengths in both cases, but Amin did not appear to be influenced. Both γcmc and Amin appeared independent of the ester group orientation. Notably, alkyl (methyl α-d-glucopyranosid)uronates were found to result in noticeably lower CMC, possibly due to a closer distance between the carbonyl function and the head group.

Research Progress of eco-friendly Sugar-based Surfactants

Surfactant is a common industrial product widely used in chemical industry, food production, biomedicine and other fields. A variety of glucose-based bisubstituted surfactants have been developed, which not only contain the advantages of other classes of sugar-based surfactants, but also have the properties of mild conditions of use, good bactericidal ability, and non-irritation of the skin, etc. In addition, sugars are widely sourced and renewable, and the production of sugar-based surfactants with degradability has become a hot spot of the current research. This paper summarises the types of common sugar-based surfactants, the test methods of related properties and the application prospects.

Theoretical Evaluation of Eco-friendly Designed Nonionic Sugar-based Surfactants

Abstract: This study deals with the density functional theory calculations of eco-friendly designed nonionic sugar-based surfactants (SurfRing and SurfLinear). Then, it compares the results with the structural and electronic properties of a fatty alcohol surfactant (SurfFA). All geometry optimizations and energy calculations were performed using M06-2X functional and 6-31G(d,p) basis sets. The quantum chemistry reactivity parameters showed the effect of hydrophilic fragment structure on intramolecular interactions and conformational stability of surfactants. The results showed that SurfRing is more reactive than SurfFA. Based on Bader’s quantum theory of atoms in molecules (QTAIM), one intramolecular hydrogen bond (O43…H67―O57, EHB: -11.9 kcal.mol-1) is characterized for SurfRing, while two hydrogen bond interactions (O63…H60―O59 and O65…H64―O63 with EHB of -13.0, and -12.3 kcal.mol-1, respectively) form between the hydroxyl groups of SurfLinear. These intramolecular hydrogen bonds are partially covalent interactions. Natural bond orbital analysis reveals that the most prominent interaction energy is electron donation from the oxygen atom lone pair to the antibonding orbital of the O―H bond supporting the results obtained from the AIM calculations.

Sugar-Based Monoester Surfactants: Synthetic Methodologies, Properties, and Biological Activities.

Glycolipids are biocompatible and biodegradable amphiphilic compounds characterized by a great scientific interest for their potential applications in various technological areas, including pharmaceuticals, cosmetics, agriculture, and food production. This report summarizes the available synthetic methodologies, physicochemical properties, and biological activity of sugar fatty acid ester surfactants, with a particular focus on 6-O-glucose, 6-O-mannose, 6-O-sucrose, and 6'-O-lactose ones. In detail, the synthetic approaches to this class of compounds, such as enzymatic lipase-catalyzed and traditional chemical (e.g., acyl chloride, Steglich, Mitsunobu) esterifications, are reported. Moreover, aspects related to the surface activity of these amphiphiles, such as their ability to decrease surface tension, critical micelle concentration, and emulsifying and foaming ability, are described. Biological applications with a focus on the permeability-enhancing effect across the skin or mucosa, antimicrobial and antifungal activities, as well as antibiofilm properties, are also presented. The information reported here on sugar-based ester surfactants is helpful to broaden the interest and the possible innovative applications of this class of amphiphiles in different technological fields in the future.

Enhanced solubilization of strongly adsorbed organic pollutants using synthetic and natural surfactants in soil flushing: Column experiment simulation

This study investigates the performance of two non-ionic sugar-based surfactants, belonging to the families of synthetic alkylpoliglucosides and biological rhamnolipids, for enhancing the solubilization and mass transfer of strongly adsorbed hydrophobic organic compounds (HOCs) in porous media. Using toluene and perchloroethylene (PCE) as reference pollutants, a continuous configuration test (column experiment) was performed to simulate a soil flushing process under controlled laboratory conditions. The potential applicability of the selected surfactants in remediation processes was evaluated within the context of Surfactant Enhanced Aquifer Remediation (SEAR) technology. Experimental results showed that both surfactants effectively increased the solubilization of contaminants adsorbed on porous media. Compared to H2O flushing, synthetic surfactant increased the solubilization of toluene by 52% and the solubilization of PCE by 81%, while biosurfactant increased solubilization ability by 73% and 92% for toluene and PCE, respectively. Biosurfactant exhibited the greatest solubilization ability, with 92% of adsorbed toluene and 98% of adsorbed PCE solubilized. This research highlights the potential of green surfactants as efficient candidates for remediation processes due to their excellent solubilization ability and environmentally friendly nature.

Performance of alkyl β-D-maltosides in molecular self-assembly and formation of oil-in-water nanoemulsions as drug delivery systems

Alkyl β-D-maltosides are nonionic sugar-based surfactants that can be used as excipients in lipid-based nanoparticles because of their physiological functions and biocompatibility. The self-assembly of alkyl β-D-maltosides (C8-C12) was studied to investigate the effects of alkyl chain length in the binary and ternary systems. Surface tension measurements in the binary systems revealed a synergistic effect on the stability of mixed surfactants with Tween 80 (T80) in the critical aggregation concentration (CAC). Subsequently, formulations of 10:90 wt% oil-in-water (O/W) nanoemulsions (ternary systems) containing T80/alkyl β-D-maltosides with and without cyclosporine (CsA) as the hydrophobic model drug were characterised by particle size, polydispersity index (PDI), morphology, rheology, and physical stability. The formulations of all nanoemulsion systems were found to be stable against phase separation for 28 days at room temperature. The hydrophobic effect of n-dodecyl-β-D-maltoside (DDM, C12) was stronger by enhancing the stability of T80 nanoemulsion in molecular self-assembly compared to the shorter chains of the maltosides. The in vitro drug release study showed that T80/DDM nanoemulsion improved the cumulative release of CsA in 24 h by 98.33 ± 7.72% compared to T80 nanoemulsion at 83.75 ± 4.05%. The release of CsA has the highest fit with the Korsmeyer-Peppas kinetic model (R2 > 0.9), suggesting that CsA is released slowly from the oily core of nanoemulsions to the dissolution medium due to its hydrophobic nature. The cytotoxicity study against 3T3 cells showed that all formulations had no cytotoxicity effect (IC50) up to 500 μg/mL. The findings demonstrated that T80/DDM nanoemulsion holds great promise as a drug delivery system for the treatment of psoriasis.

Surface-modified cerium dioxide nanoparticles with improved anti-amyloid and preserved nanozymatic activity

Cerium dioxide nanoparticles (CeO2 NPs) are used increasingly in nanotechnology and particularly in biotechnology and bioresearch. Thus, CeO2 NPs have been successfully tested in vitro as a potential therapeutic agent for various pathologies associated with oxidative stress, including the formation of protein amyloid aggregates. In this study, to increase the anti-amyloidogenic efficiency and preserve the antioxidant potential, the surface of the synthesized CeO2 NPs is modified with a nonionic, sugar-based surfactant, dodecyl maltoside (DDM), which is known for its high anti-amyloidogenic activity and biocompatibility. Dynamic light scattering and Fourier transform infrared spectroscopy demonstrated successful modification by DDM. The apparent hydrodynamic diameters of CeO2 NPs and DDM-modified NPs (CeO2@DDM NPs) are found to be ⁓180 nm and ⁓260 nm, respectively. A positive zeta potential value of + 30.5 mV for CeO2 NPs and + 22.5 mV for CeO2 @DDM NPs suggest sufficient stability and good dispersion of NPs in an aqueous solution. A combination of Thioflavin T fluorescence analysis and atomic force microscopy is used to assess the effect of nanoparticles on the formation of insulin amyloid fibrils. Results show that the fibrillization of insulin is inhibited by both, naked and modified NPs in a dose-dependent manner. However, while the IC50 of naked NPs is found to be ∼270 ± 13 µg/mL, the surface-modified NPs are 50% more efficient with IC50 equaled to 135 ± 7 µg/mL. In addition, both, the naked CeO2 NPs and DDM-modified NPs displayed an antioxidant activity expressed as oxidase-, catalase- and SOD-like activity. Therefore, the resulting nanosized material is very well suited to prove or disprove the hypothesis that oxidative stress plays a role in the formation of amyloid fibrils.

Development of trisiloxane surfactant vesicles ultrasonic extraction method combined with ultrahigh-performance liquid chromatography tandem mass spectrometry for the rapid differentiation of Bupleuri Radix based on metabolomics.

Due to the variety, chemical composition and complex structure, the quality control of Bupleuri Radix (BR) is a challenging task. There are still many trace compounds in BR that are difficult to extract and detect. To develop an innovative method of trisiloxane surfactant vesicles ultrasonic extraction (TSVUE) combined with ultrahigh-performance liquid chromatography tandem mass spectrometry for the identification from Bupleurum chinense DC. (BC) to Bupleurum scorzonerifolium Willd (BS) based on metabolomics. Based on extraction effect for BR, five different types of surfactants vesicles were prepared and compared. Then, a single-factor test and a response surface methodology study were adopted to obtain the optimal conditions for the surfactant vesicles ultrasonic extraction method. Finally, a non-targeted metabolomics method with information dependent acquisition mode was performed to analyse differential metabolites in BC and BS. Sugar-based surfactant containing trisiloxane [N-3-propyl-methyltrisiloxane-N-glucoheptonamne (Si(3)N-GHA)] displayed higher extraction efficiency compared to other types of surfactants when it comes to being used in pretreatment methods. And a TSVUE method was established and optimised. In total, 131 constituents were identified in two BR herbs, of which 35 were unreported, and 11 were characterised as chemical markers. This method provides promising perspectives for rapidly identifying trace compounds in complex systems of traditional Chinese medicine (TCM), as well as for laying the foundation in the identification of similar herbs from the same species. Meanwhile, these findings serve as a promising application of trisiloxane surfactant vesicles in the extraction field of TCM.

Toward Sustainable Production of Sugar-Based Alkyl Polyglycoside Surfactant─A Comprehensive Review on Synthesis Route and Downstream Processing

This review aims to identify the challenges and opportunities in sustainable production of sugar-based alkyl polyglycoside, s-APG, by first assessing and subsequently comparing the production route and downstream processing for both the chemically and biologically catalyzed synthesis process, from the perspective of critical operating parameters, type of reactor technologies, and downstream processing strategies. From a sustainability point-view, the acidic homogeneous catalyst in chemically catalyzed s-APG production should be substituted by a practically active, stable, and recyclable heterogeneous catalyst. Alternatively, the green solvent could be used to increase the interaction between sugar and fatty alcohol, resulting in high yield s-APG without using a catalyst. To make the process employing biocatalyst more economically competitive, the free enzyme must be reused through the immobilization method, reactor intensified with membrane or other appropriate downstream processes. A less energy-intensive extraction process to replace the existing evaporative method to separate fatty alcohol from s-APG also deserves an intensive investigation.

Synthesis and Properties of Sucrose- and Lactose-Based Aromatic Ester Surfactants as Potential Drugs Permeability Enhancers.

The delivery of therapeutics across biological membranes (e.g., mucosal barriers) by avoiding invasive routes (e.g., injection) remains a challenge in the pharmaceutical field. As such, there is the need to discover new compounds that act as drug permeability enhancers with a favorable toxicological profile. A valid alternative is represented by the class of sugar-based ester surfactants. In this study, sucrose and lactose alkyl aromatic and aromatic ester derivatives have been synthesized with the aim to characterize them in terms of their physicochemical properties, structure-property relationship, and cytotoxicity, and to test their ability as permeability enhancer agents across Calu-3 cells. All of the tested surfactants showed no remarkable cytotoxic effect on Calu-3 cells when applied both below and above their critical micelle concentration. Among the explored molecules, lactose p-biphenyl benzoate (URB1420) and sucrose p-phenyl benzoate (URB1481) cause a reversible ~30% decrease in transepithelial electrical resistance (TEER) with the respect to the basal value. The obtained result matches with the increased in vitro permeability coefficients (Papp) calculated for FTIC-dextran across Calu-3 cells in the presence of 4 mM solutions of these surfactants. Overall, this study proposes sucrose- and lactose-based alkyl aromatic and aromatic ester surfactants as novel potential and safe permeation enhancers for pharmaceutical applications.

Micelle-Derived Palladium Nanoparticles for Suzuki–Miyaura Coupling Reactions in Water at Room Temperature

Despite the wide utility of colloidal palladium (Pd) nanoparticle (NP)-catalyzed Suzuki–Miyaura cross-coupling reactions in laboratory and industrial synthesis, the easy construction of colloidal Pd NPs and the detailed role of surfactants remain the focus of attention. Here, we present a simple and sustainable strategy to construct a nanoreactor by connecting micelles with Pd NPs. The strategy enables us to employ a pH-induced morphological transition of sugar-based surfactant aggregates, such as worm-like, spherical, and tubular micelles, to investigate the solubilization of organic substrates. Pd NPs are mainly synthesized by the reduction of phenylboronic acid, further stabilized by the sugar-based surfactant micelles. A kinetic model is established, and the apparent activation energy of this reaction in aqueous micellar solutions is determined to be 46.7 kJ/mol. Notably, the recycled aqueous reaction mixture containing the micelles and Pd NPs can be reused.

An efficient and green procedure for transformation of thiols to disulfides and thioamides in AGA8 aqueous micelles

A sugar-based surfactant AGA8 was designed and demonstrated to promote the synthesis of disulfides and thioamides in water.

The relationship between the chemical structure, physicochemical properties, and mucosal adjuvanticity of sugar-based surfactants

The relationship between the chemical structure, physicochemical properties, and mucosal adjuvanticity of sugar-based surfactants (SBSs) has not been sufficiently elucidated. Thus, in the present study, we systematically analyzed 11 SBSs for mucosal adjuvanticity. Ovalbumin (OVA)-specific antibody titers were measured in mice immunized intranasally with OVA plus SBS. We found that four SBSs (trehalose monododecanoate, sucrose monododecanoate, n-dodecyl-α-d-maltopyranoside, and n-dodecyl-β-d-maltopyranoside) exhibited the most potent adjuvanticity. We identified the following associations between chemical structure and adjuvanticity: 1) OVA-specific antibody titer increased with an increasing number of carbon atoms in the alkyl chain; 2) the adjuvanticity was not affected by the type of sugar or bond between the sugar and alkyl chain; and 3) SBSs with rigid structures exhibited less adjuvanticity. The relationship between physicochemical properties and adjuvanticity was as follows: 1) SBSs exhibited adjuvanticity above the critical micelle concentration and 2) in the SBSs with potent adjuvanticity, the diameter of the SBS-OVA complex was 70–75 nm. Our study indicates evidence for the direct involvement of chemical structure and physicochemical properties in determining adjuvanticity in SBSs.

Synthesis of d-Gluconic Acetal Surfactants and Their Foaming Behaviors.

Sugars are natural and environmentally benign substances, which can offer various hydroxyl groups. The understanding of details of the hydroxyl interactions in the hydrophilic groups of sugar-based surfactants, as well as the related properties, is still indistinct. Here, novel d-gluconic acetal surfactants with bicyclic and monocyclic structures in the head group were designed and synthesized. The obtained surfactant with a bicyclic architecture exhibited excellent foamability and a multistimulus-responsive behavior toward foam stabilization. In addition, the control of foamability from defoaming and foaming could be achieved by changing pH values or bubbling gas of CO2/N2. To explore the structural effects such as hydroxyl groups and rigidity of the head group on the properties of sugar-based surfactants, another kind of amphiphilic molecule with various OH- groups and a monocycle in the head group was designed for comparison. These two series of amphiphilic molecules both exhibited good surface activity. However, only the d-gluconic acetal surfactant with a bicyclic structure and a smaller number of OH- groups exhibited excellent foamability. Further studies showed that the foam behaviors were attributed to the conformation and arrangement of the surfactant molecule at the surface layer with the assistance of hydrogen bonds formed by hydroxyl groups and H2O molecules. In addition, the surfactant could provide an environmentally friendly foamer in many potential applications.

Improving the Processability and Performance of Micronized Fiber-Reinforced Green Composites through the Use of Biobased Additives.

Green composites made of bioplastics reinforced with natural fibers have gained considerable attention over recent years. However, the use of natural fibers in composites usually compromise some key properties, such as the impact strength and the processability of the final materials. In the present study, two distinct additives, namely an epoxidized linseed oil (ELO) and a sugar-based surfactant, viz. GlucoPure® Sense (GPS), were tested in composite formulations of poly(lactic acid) (PLA) or poly(hydroxybutyrate) (PHB) reinforced with micronized pulp fibers. Both additives showed a plasticizing effect, which led to a decrease in the Young’s and flexural moduli and strengths. At the same time, the elongation and flexural strain at break were considerably improved on some formulations. The melt flow rate was also remarkably improved with the incorporation of the additives. In the PHB-based composites, an increment of 230% was observed upon incorporation of 7.5 wt.% ELO and, in composites based on PLA, an increase of around 155% was achieved with the introduction of 2.5 wt.% GPS. ELO also increased the impact strength to a maximum of 29 kJ m−2, in formulations with PLA. For most composites, a faster degradation rate was observed on the formulations with the additives, reaching, in the case of PHB composites with GPS, a noteworthy weight loss over 75% under burial testing in compost medium at room temperature.

Topological Dynamics of Micelles Formed by Geometrically Varied Surfactants

The molecular architecture of sugar-based surfactants strongly affects their self-assembled structure, i.e., the type of micelles they form, which in turn controls both the dynamics and rheological properties of the system. Here, we report the segmental and mesoscopic structure and dynamics of a series of C16 maltosides with differences in the anomeric configuration and degree of tail unsaturation. Neutron spin-echo measurements showed that the segmental dynamics can be modeled as a one-dimensional array of segments where the dynamics increase with inefficient monomer packing. The network dynamics as characterized by dynamic light scattering show different relaxation modes that can be associated with the micelle structure. Hindered dynamics are observed for arrested networks of worm-like micelles, connected to their shear-thinning rheology, while nonentangled diffusing rods relate to Newtonian rheological behavior. While the design of novel surfactants with controlled properties poses a challenge for synthetic chemistry, we demonstrate how simple variations in the monomer structure can significantly influence the behavior of surfactants.