Polyoxyethylene Chain Research Articles

Modulation of Lipid Digestion by Nanoarchitectonics of Complex Interfacial Structures with Tween 80 and Lecithin.

In recent years, there has been a growing interest in regulating lipid digestion through the construction of various interfacial structures. In the present work, a series of complex interfacial structures were designed by combining Tween 80 in the aqueous phase and lecithin in the oil phase at different concentration ratios. The emulsification properties, the roles in regulating lipid digestion, and the interfacial dilatational rheological properties of the composite emulsifying systems were characterized. The results showed that the combination of Tween 80 and lecithin at different ratios could effectively modulate the rate of lipid digestion. The polyoxyethylene chains of Tween 80 formed a network, that provided a spatial obstacle for the adsorption of bile salts and lipases. Thus, Tween 80 significantly delayed the lipid digestion. The introduction of lecithin gradually replaced Tween 80 molecules at the interface, thus providing space for the adsorption of bile salts and lipases. In addition, as the ratio of lecithin concentration to Tween 80 increased, lecithin gradually became the dominant factor in the interfacial properties. As a result, the rate of lipid digestion was accelerated. Therefore, by compounding different ratios of lecithin and Tween 80, a series of emulsions with different lipid digestion rates were obtained. This research provides a basis for rationally designing food emulsions according to specific needs.

Aggregation Behavior of Ethoxylated Phytosterol Surfactants in Different Protic Solvents: An Insight from Dielectric Relaxation Studies.

The micellar aggregation behavior of biocompatible surfactants, phytosterol ethoxylates (BPS-n, n is the oxyethylene (EO) chain length), containing polyoxyethylene chains in four organic solvents (glycerol (G), ethylene glycol (EG), formamide (FA), and N,N-dimethylformamide (DMF)) was studied by dielectric spectroscopy in the frequency range of 40 Hz to 110 MHz. Only the BPS-n/EG and BPS-n/G systems show distinct dielectric loss peaks near 104 Hz, indicating that BPS-n forms micellar aggregates in EG and G solvents, and the interfacial polarization (IP) between the aggregates and solvents leads to this relaxation. The dielectric spectra were analyzed based on the IP theory and a columnar dispersion model. The dielectric parameters of micelles, the permittivity and conductivity of micelles and solvents, and the volume fraction of the aggregates in solvents were calculated. On this basis, the binding numbers of each EO group on the hydrophobic chain to the solvent molecules EG and G were calculated to be 0.42 and 0.22, respectively. It was suggested that the aggregation appears to be related to the magnitude of the hydrogen bonding interactions. The lower number of EO group-binding solvents is because of the strong steric effect of alcohol solvents and the magnitude of the hydrogen bonding force.

The formation and temperature stability of microemulsion emulsified by polyoxyethylene ether surfactant

The effect of polyoxyethylene chain length on the formation and temperature stability of W/O microemulsion emulsified by polyoxyethylene ether surfactant is investigated by dissipative particle dynamics simulation (DPD) on the mesoscopic level. The results show that W/O microemulsions can be formed by three polyoxyethylene chain length ether nonionic surfactants with decreasing the water-oil ratio equal to increasing the oil phase content. However, W/O microemulsion is most easily formed by diethylene glycol monododecyl ether (H1T2) with the smallest oxyethylene base.The results of temperature stability show that W/O microemulsion emulsified by H1T2 has better stability resistant to high or low temperature. In addition, the interfacial tension of the W/O microemulsion system is the lowest, the end-to-end distance of the surfactant molecule is smallest, and the molecular chain is the most curved at the water-oil interface. The theoretical simulation results can guide the formation of the W/O microemulsion induced by polyoxyethylene ether nonionic surfactant, and provide the guidance for its practical application.

Synthesis and application of nonionic Gemini surfactants based on grape seed oil

AbstractA series of vegetable oil‐based nonionic Gemini surfactant (GPNGS) was prepared using grape seed oil and polyethylene glycol monomethyl ether (350, 550, 750) as the primary raw materials. The chemical structures of different types of GPNGS were characterised by Fourier Transform–infrared spectroscopy, elemental analysis, proton nuclear magnetic resonance and carbon‐13 nuclear magnetic resonance. The critical micelle concentration (CMC) of GPNGS with different polyoxyethylene chain lengths was measured using the Wilhelmy ring method (CMC: ca. 1.4 × 10−4 to 5 × 10−4 mol/L). The results of wettability testing showed that the contact angle of GPNGS on polyamide film was ca. 46‐49°. In addition, the interaction of surfactants with acid dyes was also investigated. The ultraviolet spectrum showed a balance between dyes, surfactants and the dye/surfactant complex. Next, the GPNGS was used as a nylon 66 acid dye levelling agent. After adding 0.2 mmol/L of surfactants, the standard deviations (S(λ)) of nylon 66 dyeing decreased from 0.084 to ca. 0.036‐0.044, exhibiting a good levelling effect.

Polyethylene glycol regulated carnallite decomposition-crystallization: Experimental and theoretical analysis

Currently, the “crystallization-flotation” process is widely used for the industrial production of KCl. However, the significant aggregation of KCl and NaCl in the decomposition-crystallization stage of carnallite leads to inefficient separation of the two particles in the flotation stage, which restricts the production of high-grade KCl. In this study, environmentally friendly polyethylene glycol (PEG) was used to regulate the decomposition-crystallization of carnallite for the first time, and the high-grade KCl was successfully prepared by reducing the degree of crystal aggregation. The crystals were characterized by SEM-EDS, FT-IR, XRD and AFM, and it was found that PEG which average Mn 800 (PEG 800) could adsorb on the crystal surface and effectively disperse NaCl and KCl. It was also found that there are two mechanisms by which PEG 800 achieves dispersion. On the one hand, PEG 800 micelles contain polyoxyethylene chains with large steric repulsion, which can prevent the adhesion of particles. On the other hand, PEG 800 can weaken the electric potential on the surface of KCl and NaCl and reduce the electrostatic interaction force between the particles. Finally, the behavior of Na, K, and Cl before and after the addition was simulated by molecular dynamics, and molecular dynamics calculations showed that PEG 800 could weaken the effect of NaCl on KCl.

Synergistic effects of Gemini cationic surfactants with multiple quaternary ammonium groups and anionic surfactants with long EO chains in the mixed systems

In this study, two different anionic surfactants containing long polyoxyethylene chains involving sodium fatty alcohol ether carboxylates (AE9C) as well as isomeric sodium fatty alcohol ether sulfates (iso-AE9S) are mixed with a new Gemini cationic surfactant bearing four quaternary ammonium groups (TC-GS). Then, the surface properties and aggregation behavior of the two mixed systems were investigated. The effect of the long polyoxyethylene chains on the conformation and hydration of the hydrophilic head group of AE9C and iso-AE9S weakened their negative charge density, thus hindering their excessive electrostatic adsorption with TC-GS and improving the stability of the mixed systems. The positive synergistic effects of TC-GS/AE9C and TC-GS/iso-AE9S exhibited significantly lower critical micelle concentration, faster diffusion rates, and superior wetting capability compared to single surfactants. The micellization process of both mixed systems is spontaneously enthalpy-driven, and the diffusion-adsorption process is consistent with the mixed diffusion-kinetic mechanism. Finally, both mixed systems are capable of forming complex and interesting aggregate morphologies, with TC-GS/AE9C can form multilayer spherical vesicles and TC-GS/iso-AE9S can form multicompartment concentric spherical vesicles.

Enhanced the permeability of water invasion sandstone by effectively inhibiting the swelling and dispersion of montmorillonite

The long-term effect of protecting water-sensitive reservoirs and enhancing permeability of water invasion reservoir is still an urgent practical problem to be solved. Here, an imidazolium Gemini ionic liquid (IL), PEG-DC8Im, with octyl as tail chain and polyoxyethylene chain as bridging group, was synthesized to inhibit the hydration, swelling and dispersion of clay minerals. The PEG-DC8Im could exert excellent anti-swelling ability (93.82 %) and outstanding washable capacity (cumulative decrease of anti-swelling rate after being washed five times: 1.32 %) at the concentration of 60 mmol/L. The inhibition effect of 20 mmol/L PEG-DC8Im was significantly better than that of 250 mmol/L KCl at 90 °C. And the PEG-DC8Im could intercalate into the interlayer space of MMT through cation exchange to play an inhibition effect, where zeta potential of MMT particles was reduced and then the dispersion ability of MMT was weakened. Subsequently, the anionic polymer poly(AM/AA) was found to cooperate with PEG-DC8Im to improve the inhibition effect for MMT swelling and dispersion, in which poly(AM/AA) was not intercalated into the interlayer of MMT, and only adsorbed on the surface of the particles to encapsulate the MMT particles. Simultaneously, the apparent viscosity and thixotropy of the composite solution were enhanced. Besides, after the treatment of PEG-DC8Im, the displacement pressure decreased and the permeability of sandstone cores increased due to the inhibition of clay mineral hydration, revealing the enhancement of injectivity. Finally, the pore connectivity of the core increased and the water wettability was weakened. The treatment of PEG-DC8Im was conducive to the discharge of invasive water in reservoir and the improvement of the reservoir permeability. Overall, PEG-DC8Im has a good application prospect as permeability-enhancing clay stabilizers.

Effects of inorganic metal ions on the mixture of single polyoxyethylene chain carboxylate surfactant and Gemini quaternary ammonium surfactant

Complexation mechanisms of polyoxyethylene group and amide group with metal ions were confirmed by a simple method.

Preparation of polyoxypropylene surfactant-based nanoemulsions using phase inversion composition method and their application in oil recovery

Emulsification using phase inversion composition (PIC) was achieved by changing the composition of surfactants at a constant temperature. The method has great potential to scale up applications due to the ease in the formation of nanoemulsions and the relatively low energy involved. Surfactants containing composition-sensitive polyoxyethylene (POE) chains are widely used to prepare nanoemulsions using the PIC method. It is, therefore, anticipated that surfactants containing composition-sensitive polyoxypropylene (POP) chains can also be used to prepare nanoemulsions using the PIC method. The POP surfactant D230-2OA, containing short POP chains, was obtained from the electrostatic interactions between hydrophilic POP diamine (D230) and hydrophobic oleic acid (OA). The synthesized D230-2OA was used as an emulsifier in the preparation of the n-dodecane-in-water nanoemulsion using the PIC method. The effects of D230-2OA concentration, oil-to-surfactant weight ratio, and NaCl concentration on the droplet size of the nanoemulsions was investigated using dynamic light scattering (DLS). The morphology of the nanoemulsion was characterized using cryogenic transmission electron microscopy (cryo-TEM). The wettability of the crude oil–saturated quartz plate before and after treatment with nanoemulsions was obtained using contact angle measurement. A core flooding experiment demonstrated the efficiency of the diluted nanoemulsion in enhanced oil recovery, with an additional recovery of 21.30%. The nanoemulsion prepared with the POP surfactant as the emulsifier using the PIC method has wide application in petroleum recovery.

Mixtures of anionic surfactants with single/triple polyoxyethylene chains and Gemini quaternary ammonium surfactant: interaction and surface activity studies

The combination of anionic and cationic surfactants can obtain high surface activity so that it has been widely used in many fields. However, the problem of ease to precipitate in the isoelectric mole ratio limits its further application. The introduction of polyoxyethylene chain into anionic surfactant and the use of Gemini quaternary ammonium surfactant can solve this problem origin from excessively strong interaction to a great extent while maintaining the best surface activity of the mixed system. Single polyoxyethylene chain carboxylate and triple polyoxyethylene chains sulfonate surfactants are mixed with Gemini quaternary ammonium surfactant respectively and their interactions are explored. The experimental results show that the complex of anionic surfactants with single or triple polyoxyethylene chains and Gemini quaternary ammonium surfactant can obtain high surface activity. And the polyoxyethylene group weakens the charge density of hydrophilic head groups of anionic surfactants. The branched polyoxyethylene chains will weaken this weakening effect. Excessively large steric hindrance of surfactant may reduce the stability and surface activity of mixed system. For anionic nonionic surfactants, the single chain structure and the appropriate numbers of polyoxyethylene groups are more conducive to compounding with Gemini quaternary ammonium surfactants to obtain the best surface activity and the most stable solution.

Reductive Methylation of Homogeneous Primary β-Lauryl/myristyl 7/3 Polyethyleneoxy n = 3-18 Ethylamines under Phase-Transfer Catalysis Conditions.

Homogeneous tertiary N,N-dimethyl-N-β-lauryl/myristyl 7/3 polyethyleneoxy n = 3–18 ethylamines, LM(EO)nAT, are niche intermediates in the synthesis of homogeneous N-alkyl (C1–C18)-N,N-dimethyl-N-β-lauryl/myristyl 7/3 polyethyleneoxy n = 3–18 ethylammonium chlorides (unitary degree of oligomerization of ethylene oxide in the polyoxyethylene chain). This paper synthetically presents the dependence of the reductive methylation yields of homogeneous primary β-lauryl/myristyl 7/3 polyethyleneoxy n = 3–18 ethylamines, LM(EO)nAP, on the reaction time (10–90 min), the temperature (70 °C), the molar ratio formic aldehyde /LM(EO)nAP (1.1/1–2.5/1), the molar ratio HCOOH/LM(EO)nAP (5/1), the degree of oligomerization of ethylene oxide in the homogeneous polyoxyethylene chain in the 3,6,9,12,18 series, and the structure of the phase-transfer catalysts. The steric effects of hydrophobic groups CH3 and C18H37 grafted onto the ammonium function, and the micellar phenomena in the vicinity of their critical micellar concentration, directly proportional to the homogeneous degree of oligomerization, were highlighted. In all cases, a steady increase in reductive methylation yields was observed, with even quantitative values obtained. The high purity of the homologous series LM(EO)nAT will allow their personalization as reference structures for the study of the evolution of basic colloidal characteristics useful in forecasting technological applications. LM(EO)nAP were obtained either by direct amidoethylation (nucleophilic addition under basic catalysis of homogeneous lauryl/myristyl 7/3 polyethoxylated n = 3, 6, 9, 12, 18 alcohols, LM(EO)nOH, to acrylamide monomer) or by cyanoethylation of LM(EO)nOH under basic catalysis at 25–50 °C, in the presence of Fe2+ cations as oligomerization/polymerization inhibitor, followed by partial acid hydrolysis of homogeneous β-alkyl (C12H25/C14H29) 7/3 polyethyleneoxy n = 3, 6, 9, 12, 18 propionitriles, LM(EO)nPN, to β-alkyl (C12H25/C14H29) 7/3 polyethyleneoxy n = 3, 6, 9, 12, 18 propionamides, LM(EO)nPD, which led to LM(EO)nAP by Hoffmann degradation. Homogeneous higher tertiary polyetheramines LM(EO)nAT were structurally characterized.

Effect of Oxyethylene Groups on Adsorption Properties of Fatty Alcohol Polyoxyethylene Ether Sodium Sulfate with Narrow Ethylene Oxide Distribution

Abstract The effect of oxyethylene groups on the adsorption properties of fatty alcohol polyoxyethylene ether sodium sulfate with narrow ethylene oxide distribution (AEmS, m = 3, 5, 7, 9) was characterized by means of the equilibrium surface tension, the dynamic surface tension and the contact angle. The results show that at a concentration lower than the critical micelle concentration (CMC) the oxyethylene groups act like hydrophobic groups to change the absorption properties. If the concentration is higher than the critical micelle concentration, the oxyethylene groups act as hydrophilic groups to change the absorption properties. The long polyoxyethylene chain of AE9S is very curly, which means that AE9S does not strictly follow the rule derived from AEmS (m = 3, 5, 7). The adsorption process of AEmS is a mixed diffusion-kinetic adsorption mechanism.

Thermoresponsive behaviors of novel polyoxyethylene-functionalized acrylamide copolymers: Water solubility, rheological properties and surface activity

Herein, a series of polyoxyethelene-functionalized polymers were synthesized using acylamide (AM), acryl acid (AA), various allyl polyoxyethelene ethers as monomers via facile redox-initiated free radical copolymerization. The polyoxyethylene chains contributed to improving solubility, while the introduction of alkyl prolonged the dissolution time of polymers. Heating and addition of electrolyte caused alkyl-containing polymers to dissolve worse due to the weakening of hydration of oxyethylene units. Subsequently, in rheological studies, alkyl-capped polyoxyethylene-functionalized polymers showed strong thickening ability, excellent shear resistance and viscoelasticity. Obviously, polymer with more oxyethylene units was prone to achieve better rheological properties. Alkyl-containing polymers exerted better elasticity, and the intersections of elastic and viscous moduli was at lower oscillation frequency (around 0.01 Hz), owing to intermolecular association. Besides, the response of alkyl-containing polymers to temperature presented thermothickening behavior, differing from monotonous downward of conventional polymers. Their viscoelasticity was improved in the range of 20–50 °C, especially for polymers with more oxyethylene groups. Importantly, alkyl-capped polyoxyethelene chains endowed polymers with surface activity, which reduced surface tension to about 40 mN/m and maintained emulsification rate above 50% after 30 h at the polymer concentration of 2000 mg/L. This study provides valuable guidance for the design and application of fast-dissolving and temperature-resistant polymers.

Development and validation of eco-friendly micellar HPLC method for the simultaneous determination of hydrochlorothiazide and valsartan in bulk powder and pharmaceutical dosage forms

Ongoing greener in chromatography, new methodologies have to be developed using safer mobile phase composition and/or lower solvent consumption. The new methods should also consider the applicability in industrial facilities where selection criteria are based mainly on profit through cost and time. The drugs under study, valsartan (VAL) and hydrochlorothiazide (HCT), are co-formulated as tablet dosage form which is considered a widely consumed first-line treatment for hypertension. The use of the biodegradable non-ionic surfactant Brij-35 (0.1 M) in the aqueous phase increased the surface polarity of the bonded C18 stationary phase by its polyoxyethylene chain. This change gave faster separation of the analytes in short analysis time, enabled the use of methanol instead of acetonitrile which is more environmentally safe and also decreased its ratio required to enhance elution to only 25%. Fast isocratic separation was achieved at flow 1 mL min−1 where the retention times were 2.9 and 4.3 min for VAL and HCT, respectively, using UV detection at 254 nm. The method was validated according to ICH guidelines. High accuracy results were obtained at linearity range of 5–100 µg mL−1 for both drugs. LOD and LOQ were (1.01 and 3.05 µg mL−1) for VAL and (1.01 and 3.09 µg mL−1) for HCT, respectively. The method was successfully applied for determination of the drugs in their marketed dosage form. Since claiming greenness is not enough, the proposed method was compared favorably with published methods using the new assessment tool, GAPI index.

Systematic Investigation of the Effect of Non-Ionic Emulsifiers on Skin by Confocal Raman Spectroscopy-A Comprehensive Lipid Analysis.

Non-ionic emulsifiers are commonly found in existing pharmaceutical and cosmetic formulations and have been widely employed to enhance the penetration and permeation of active ingredients into the skin. With the potential of disrupting skin barrier function and increasing fluidity of stratum corneum (SC) lipids, we herein examined the effects of two kinds of non-ionic emulsifiers on intercellular lipids of skin, using confocal Raman spectroscopy (CRS) with lipid signals on skin CRS spectrum. Non-ionic emulsifiers of polyethylene glycol alkyl ethers and sorbitan fatty acid esters were studied to obtain a deep understanding of the mechanism between non-ionic emulsifiers and SC lipids. Emulsifier solutions and dispersions were prepared and applied onto excised porcine skin. Water and sodium laureth sulfate solution (SLS) served as controls. SC lipid signals were analysed by CRS regarding lipid content, conformation and lateral packing order. Polyethylene glycol (PEG) sorbitan esters revealed no alteration of intercellular lipid properties while PEG-20 ethers appeared to have the most significant effects on reducing lipid content and interrupting lipid organization. In general, the polyoxyethylene chain and alkyl chain of PEG derivative emulsifiers might indicate their ability of interaction with SC components. HLB values remained critical for complete explanation of emulsifier effects on skin lipids. With this study, it is possible to characterize the molecular effects of non-ionic emulsifiers on skin lipids and further deepen the understanding of enhancing substance penetration with reduced skin barrier properties and increased lipid fluidity.

Polystyrene networks with polyoxyethylene cross-links covalently grafted onto nano-SiO2 cores: surface-initiated ATRP and thermal investigations

Cross-linked polystyrene loaded by silica nanoparticles (CPS/SNPs) with hydrophilic nature was prepared via a solvent-free surface-initiated atom transfer radical polymerization technique. Chemical immobilization of the initiator of the polyaddition reactions was performed on silica nanoparticles. Also, polyoxyethylene chains capped with styrenic end units were synthesized from the reaction of 4-chloromethyl styrene and polyethylene glycol with mole ratios of 2:1 and then used as the chain cross-linker. In addition to CPS/SNPs composite, a cross-linked material lacking silica cores (CPS) was also prepared by a similar technique. Thermal stabilities of the resulting cross-linked polystyrenes were fully investigated by thermogravimetric analysis/differential thermogravimetry. The silica-containing cross-linked material clearly showed more thermal stability than the bare material. In addition, both CPS/SNPs and CPS presented thermal stabilities nearly as much as other polystyrene–silica materials reported in the literature. Thus, the polyoxyethylene cross-links did not cause additional thermal sensitivity in the network obtained. Furthermore, differential thermal analysis measurements demonstrated that the phase transition caused by the thermal decomposition in CPS/SNPs composite is significantly reduced due to the presence of silica cores.

Synthesis and cytotoxicity of quercetin/hyaluronic acid containing ether block segment

This study is about preparation of natural quercetin type surfactants. The preparation involves polycondensing quercetin (QT) and propylene glycol in the presence of an acid catalyst so as to make quercetin more water soluble; performing ring opening polymerization between polyoxyethylene chains (MW: 2000, 4000, 6000, 8000, 10,000) changed by polyethylene glycol and succinic anhydride so as to obtain an ether block surfactant; and then introducing hydrolyzed hyaluronic acid (HA) by means of esterification while preparing a series of natural QT/HA-type surfactants through condensation. The synthetized products were analyzed using Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1H-NMR,13C-NMR) for their structures, and assayed for their surface active properties, including their surface tension, fluorescence, contact angles, and emulsification properties. The experimental results show that the surface activity of the QT/HA-type surfactants decreased with the ethylene oxide chain length. Among all the surfactants, the QP2H surfactant exhibited the most efficient emulsification ability, lowest surface tension, and good emulsification stability. The synthetized products were assessed for safety through in vitro cytotoxicity and MTT assays with HaCaT cell lines. According to the results, QP2H, that was similar to oil in terms of HLB value, showed outstanding emulsion stability, and its zeta potential suggested low risk of colloidal agglutination due to repulsion between its emulsion drops. However, as proven in tests with HaCaT cell lines, QT-HA containing ether block surfactants when applied in cosmetics are safe. No significant cytotoxicity was observed in any case with a concentration less than 0.01 wt% (10 mg/mL). With CMC lower than 0.01 wt%, they would not hurt skin when used in cosmetics.

Micellisation of the binary mixture of surfactants Triton X100 and Brij S10 in a water solution at T = (278.15–318.15) K: The excess Gibbs energy of the binary mixed micelles formation and its interpretation by the first order and the second order Margules function

Micellisation of the binary mixture of non-ionic surfactants Triton X100 and Brij S10 is examined. Both surfactants have polyoxyethylene chains of the same length, and differ in the conformational flexibility of the hydrocarbon segment. Triton X100 is the common surfactant in the biochemical laboratories, especially suitable for biological systems since it does not induce protein denaturation, while Brij surfactants show positive effects on the bioavailability of some drugs. According to the regular solution theory (RST), formed binary mixed micelles in each mole fraction of the binary mixture of Brij S10 – Triton X100 are richer in a hydrophobic component (Brij S10), while if the content of the binary mixed micelle is determined using the Rodenas function (the model independent method), then mixed micelles exist that are rich in Brij S10 and mixed micelles rich in Triton X100. According to the experimental values, RST hypothese that the excess entropy is zero cannot be accepted. Also, the dependence of the molar excess Gibbs energy is not a symmetric function. The RST interaction parameter as well as the model independent Gibbs energy show synergistic interactions between Brij S10 and Triton X100. In the infinitely diluted micellar pseudo-phases at T = (283.15–308.15) K the thermodynamic stabilization of Brij S10 and Triton X100 has the entropic origin.

Surface-activity of anionic–nonionic surfactants and the dispersibility of TiO2 particles in aqueous solution

This study synthesizes the anionic–nonionic surfactants by reacting tripropylene glycol, maleic anhydride, polyoxyethylenated stearyl ether and fumaric acid. The properties of a series of anionic–nonionic surfactants that feature hydrophilic groups with different lengths of chains are measured. The critical micelle concentration (CMC) value for these surfactants decreases as the length of the polyoxyethylene chain increases. This shows that long polyoxyethylene chains promote pre-micelle formation in the aqueous phase and adsorption at the interface surrounding the aqueous phase. The dispersion of a particle suspension of [Formula: see text] is also determined using dynamic light scattering (DLS) and scanning electron microscopy (SEM). The results show that when anionic–nonionic surfactants are added into a [Formula: see text] suspension, it prevents the precipitation of solid particles of [Formula: see text] and allows greater de-aggregation of the nanoparticles. DLS data show that when the concentration of the anionic–nonionic surfactants is increased, the distribution range narrows and it becomes more uniform. The larger specific surface area of the surfactant results in greater dispersion of the suspension. The SEM results show that when anionic–nonionic surfactants feature hydrophilic groups with a shorter chain, a [Formula: see text] suspension is more effectively dispersed.

Antimicrobial potentials and surface activities of novel di-Schiff base nonionic surfactants bearing unsaturated hydrophobic tails

A series of nonionic Schiff base surface active agents were prepared by the reaction between polyoxyethylene, glyoxalic acid and phenylene diamine. The compounds structures were described by means of micro-elemental analysis, infrared and proton magnetic resonance spectroscopy. The surface activities of the synthesized nonionic surface active agents at the interface were defined using the measurements of surface and interfacial tension. The thermodynamic properties of these surface active agents during adsorption and micellization processes were calculated at 25 °C. The results showed that the increase in the polyoxyethylene chain length (nonionic chains) increases their adsorption tendencies at the interface. The biological activities of the different nonionic surface active agents were measured in terms of inhibition zone diameter and rationalized to their chemical structures and surface activities.