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This article contains the information about the structure, functioning, and regeneration of type 2 pneumocytes. The composition of the surfactant, the processes of its synthesis, formation, secretion, distribution and redistribution of its components, as well as the biological role of the surfactant in the functioning of the lungs are described in detail. The information about the development of the surfactant system of the lungs during embryogenesis is also included. Objectives. To review modern literature on the structure and functions of the surfactant system of the lungs, the organization and structure of the surfactant, the mechanism of surfactant formation, the embryogenesis of the respiratory section, to characterize the structure and processes of the functioning of type 2 pneumocytes, as well as the processes of synthesis and secretion of the surfactant, its biological role in the functioning of the lungs. The relevance of the chosen topic is connected with a high level of the respiratory system pathology including a high incidence of respiratory system organs diseases in early childhood, associated with an insufficient level of the surfactant maturity. The problem of pulmonary pathology in newborns, including premature babies, largely determines the level of infant morbidity and mortality.

We studied the complexation of titanium(IV) with 2,2',3,4-tetrahydroxy-3'-nitro-5'-sulfoazobenzene (R) in the presence of cationic surfactants (CSs) cetylpyridinium chloride (CPCl), cetylpyridinium bromide (CPBr), and cetyltrimethylammonium bromide (CTMABr). In the presence of cationic surfactants, mixed-ligand complexes are formed with the ratio of components $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ : H4R– : CS = 1 : 2 : 2. The optimal pH values of the complex formation were found: 4.5 for ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2 and 3.5 for mixed-ligand complexes ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2(CPCl)2, ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2(CPBr)2, and ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2(CTMABr)2. We also investigated the effect of time, temperature, and concentrations of the reacting components on the formation of mixed-ligand complexes. The Beer law is observed in the concentration range of ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2, ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2(CPCl)2, ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2(CPBr)2, and ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2(CTMABr)2 of 0.10–1.8, 0.10–1.92, 0.10–1.92, and 0.08–1.92, respectively. The effect of foreign ions and masking substances on the determination of titanium(IV) as mixed-ligand complexes was studied. We developed a procedure for the spectrophotometric determination of trace amounts of titanium in sea sand taken from the Caspian Sea coast near the Turkan village.

In this work, the issue of surfactant adsorption (SA) onto solid surfaces was attempted through surfactant encapsulation via host-guest interactions using β-CD. Formulations of non-encapsulated (No...

Surfactant flooding is one of the chemical enhanced oil recovery (CEOR) techniques that can be used to improve oil recovery. The surfactant injection reduces the oil-water interfacial tension and mobilizes residual oil towards the producing well. In this paper, the performance of alkyl ether carboxylate (AEC) and calcium lignosulfonate (CLS) in individual and mixed surfactant systems were investigated based on their ability to reduce the interfacial tension through a spinning drop method. The interfacial tensions of individual and mixed surfactant systems in different brine systems were measured against decane at 25°C and 98°C. The results show that the individual and mixed surfactant systems in 3.5 wt.% NaCl brine has a significant reduction in interfacial tension at 98°C. In contrast, the presence of hardness in 2.5 wt.% NaCl and 1.0 wt.% MgCl2 brine reduces the interfacial tension of the individual AEC surfactant system and mixed surfactant system significantly at 98°C except for the individual CLS system. Meanwhile, the interfacial tension of mixed surfactant system decreases with increasing surfactant concentration in two brine systems and at 98°C. The findings show the significant application of the AEC and CLS surfactant mixture considering the harsh reservoir conditions for the chemical enhanced oil recovery application.

Dissipative particle dynamic (DPD) simulations were performed to study the interfacial properties such as interfacial tension, area compressibility, stress profile, and conformation of surfactant a...

Integrated and environmentally friendly methods for extraction and enrichment of natural products have gained increasing interests. The proposed preparation process provides the possibility that extraction and pre-concentration for astragalosides from Radix Astragali roots can be conducted with the surfactant aqueous system in one single procedure. The formulated surfactant system composing of 2% TX-114 as surfactant and 0.03% (w/v) of Gemini 16-5-16 as co-surfactant showed higher extraction efficiency with ultrasonic-assisted method and four astragalosides could be enriched by the cloud point phenomenon of surfactant. This work represents a valuable alternative for the eco-friendly extraction and enrichment of secondary metabolites from plants.

Barium titanate (BaTiO3) peapod nanocomposites were prepared by the controlled capture of nanoparticles (NPs) in scrolling hexaniobate (HNB) nanosheets. BaTiO3 NPs and proton-exchanged potassium hexaniobate were treated solvothermally at 220 ��C for 6 h in toluene to produce linear NP chains confined within multiwalled HNB nanoscrolls. This method consistently produced nanopeapods with average filling fractions greater than 70%. The controlled introduction of nanocomponents along with a combination of oleylamine and oleic acid surfactants was critical to the success of these reactions. The ability to form BaTiO3@HNB significantly expands the number of important peapod composites accessible by the controlled NP capture.

Due to the short time constant of the spin-spin relaxation process, there is a limitation in the preparation of NMR sample solution for large proteins. To overcome this problem, reverse micelle systems are used. Here, molecular dynamics simulation was used to study the structure of flavodoxin in a quaternary mixture of 1-decanoyl-rac-glycerol, lauryldimethylamine-N-oxide, pentane and hexanol. Hexanol was used as co-solvent. Simulations were performed at three different co-solvent concentrations. The proportion of components in the mixture was selected according to experimental conditions. For comparison, simulation of flavodoxin in water was also performed. The simulation results show that the C$\alpha$-RMSD for the protein in water is less than for the surfactant mixture. Also, the radius of gyration of flavodoxin increased in the presence of surfactants. The distance between the two residues trp-57 and phe-94, as a measure of protein activity, was obtained from the simulations. The results showed that in the surfactant mixtures this distance increases. Analysis of the secondary structure of the protein shows that the N-terminal part of the flavodoxin is more affected by surfactants. The flavodoxin diffusion coefficient in the surfactant mixture decreased in relation to its diffusion coefficient in water.

This study was focused on a ternary complex system composed of hexadecyl diphenyl ether disulfonate (C16-MADS), dodecyl dimethyl hydroxyethyl ammonium chloride (K3) and fatty alcohol polyoxyethylene ether (AEO9). The binary mixture C-K consisting of C16-MADS and K3 was investigated and the maximum synergism was obtained when the mole ratio was 0.33:0.67. Subsequently, AEO9 was added to the binary C-K complex system to investigate whether the behavior of the new complex system, in which C-K is thought to be a surfactant, can be explained by the theory of regular solution. The maximum synergism was achieved when the molar ratio of C-K and AEO9 was 7:3. The regular solution theory could well explain the synergism in mixed micelle formation and the synergism in surface tension reduction efficiency, but the synergism in surface tension reduction effectiveness did not match with the experimental data. So, there still exist some deficiencies in the application of the regular solution theory to a complex system of three surfactants.

Objective: Micellar properties of sodium dodecyl sulfate (NaDS) was examined in the presence of cetylpyridinium chloride (CPC) by means of surface tension, viscosity, dye solubilization, cloud point (CP) measurements. Antimicrobial activities of single and binary systems were also investigated. Results: A decrease in critical micelle concentration (CMC) and increase in solubilizing power for NaDS was observed with increasing CPC concentration. At the highest CPC concentration studied (0.1 M), the surface tension decreased up to 51 mN / m. Also, viscosity results showed growth in NaDS micelles (50 mM) up to the 0.1 M CPC concentration. Antimicrobial activity of NaDS, CPC and NaDS in presence of CPC was investigated against ten different strains of bacteria and ayeast which was not investigated up to now. The susceptibilities of the microorganism were determined by the agar diffusion method. The results showed that NaDS and CPC have a antimicrobial activity but NaDS in presence of CPC has not antimicrobial activity on the bacterial and yeast.

Copper contamination results in poor stability and limited application of latexes generated using emulsion ATRP. This work describes an electrolysis method, which provides for the removal of copper from such latexes, while preserving colloidal stability and latex particle integrity. Polyacrylate latexes were synthesized via emulsion polymerization with reverse ATRP. The reaction was mediated by CuCl2/4,4-di-(5-nonyl)-2,2′-bipyridine (dNbpy) and stabilized with a combined surfactant system of Brij-98 and a new surfactant-ligand (SL) design, which provides for the capture Cu species residing at the interface of latex particles. It is shown that >98% of the residual Cu was removed after 14-h of electrolysis at a voltage of 3 V, and >99% Cu removal was achieved after 7-h treatment at 9 V. For comparison, a Cu removal of

In order to reveal the growth mechanism of gold nanorods (GNRs) in a binary surfactant system, we synthesized various GNRs by changing the concentration of the surfactants, AgNO3 , and HBr in the growth solution. We found that the benzyldimethylhexadecylammoniumchloride surfactant had weak interaction with the gold ions, but it could reduce the membrane fluidity. In addition, we could dramatically decrease the cetyltrimethylammonium bromide concentration required for GNR growth by adding an HBr solution. Notably, Ag+ ions were necessary to break the symmetry of the seed crystals for GNR growth, but increasing the concentration of Ag+ and Br− ions caused a decrease in the template size.

The oil/water interfacial properties of different zwitterionic surfactant (N-dodecyl-N, N-dimethyl-3-ammonio-1-propanesulfonate, ASB; 3-(1-dodecyl-3- imidazolio)propanesulfonate, ImS3; 3-(1-dodecyl-3-benzimidazolio)propanesulfonate, BzImS3) combined with anionic surfactant (sodium dodecyl benzene sulfonate, SDBS) have been studied via experimental and simulation methods. Both experimental and simulation results indicate that the synergistic effect between surfactants is greatly affected by the aromatic cation part of the zwitterionic surfactants. For ASB/SDBS system, the SDBS and ASB molecules are adsorbed at same position of the oil/water interface, which generates competitive adsorption and resulting in a relatively loose surfactant monolayer. For ImS3/SDBS and BzImS3/SDBS systems, the additional π-π stacking interaction increases the compactness of surfactant monolayer, which contributes to the greatly reduced oil/water interfacial tension. The adsorption mechanism of mixed zwitterionic/anionic surfactant systems at oil/water interface is supplemented at a molecular level, which provides a fundamental guidance for an in-depth understanding of optimal selection of surfactant in enhancing oil recovery.

A surfactant system L64 and alcohol mixture was employed to exfoliate MoS2. To reduce the impact of surfactant on the quality of the nanosheet, the concentration of L64 was decreased to an extremely low value 0.0325 mM. Utilize common ultrasonic bath, the production yield of the nanosheet was increased to about 5% per hour, and statistical results from AFM showed that 40% of the nanosheet were less than 4 nm thick. Rheology characterization showed that surfactant alcohol mixtures were shear thinning fluid, yet the viscosity of L64 system varies directly with the shear rate in the high-speed shear region (higher than 400 s−1), and further affect the shear strength, therefore viscosity at high-speed shear can be considered as an indicator of the effectiveness for the exfoliation system. Exfoliated MoS2 was evaluated by hydrogen evolution reaction, and compared to the bulk MoS2, the 4 wt% Pt/FL-MoS2 improved the overpotential from 366 mV to 273 mV at 10 mA[Formula: see text]cm[Formula: see text]. This study presented a facile and effective route to fabricate 2D MoS2 with much less residue, and bring more opportunities to exploit clean and nontoxic system to exfoliate 2D materials.

The high thickening properties of pristine xanthan (PX) were combined with the interfacial stabilizing properties of hydrophobically modified xanthan (HMX) in order to obtain stable oil-in-water (O/W) emulsions. It was demonstrated that such a combination led to stable emulsions in which properties were higher than the sum of those of PX and HMX taken separately, thus indicating synergistic interactions between these two polymers. This synergy was confirmed when this PX/HMX couple was compared to a conventional thickener/molecular surfactant system, the latter being far less efficient. These results prove that PX and HMX interact in the emulsion contrary to classical thickening and interfacial stabilizing agents.

We report herein, the aggregation behavior of 3, 4-di(dodecyloxy)benzoic acid-4-hydroxy phenyl ester (DDBE), a synthetic amphiphile and a true non-ionic surfactant system as per the geometrical considerations. The true surfactant nature of the system stems from its hydrophilic-lipophilic-balance (HLB = 4.7), comparable to that of Span-60, also a true non-ionic surfactant. This compound undergoes spontaneous vesicle formation in THF:water binary solvent mixtures which further underwent fission at lower DDBE concentrations and fusion at higher concentrations, leading to giant vesicles of the order of 3000 nm. These vesicles are sensitive to the polarity of their environment. The predominant mode of interaction as observed from the molecular dynamics simulations were found to be π-π stacking with the phenyl rings of the molecule. Further, the system, upon complete extraction into water, formed spherical aggregates of size 50 nm based on the good solvent-poor solvent combination as the necessary condition for the vesicle formation.GRAPHICAL ABSTRACT

There is an annual increase of influenza-related SARI cases in winter months. Despite the high relevance of this problem, influenza pathogenesis and the role of surfactant system and its SP-A (surfactant protein A) enzyme in antiviral defense remain poorly understood. SP-A activates macrophage M1 polarization and triggers an antiviral response due to the activation of T-cells and dendritic cells. Therefore, surfactant system is an important element of infection protection and a promising therapeutic target.

In the present study, mixtures of gemini surfactant (T 3 H 1 S 2 H 1 T 3 ) and a conventional surfactant (A 4 B 4 ) in aqueous solutions have been investigated through coarse-grained Monte Carlo simulation. The Critical Micelle Concentration (CMC) and aggregation numbers have been calculated at different ratios of the T 3 H 1 S 2 H 1 T 3 /A 4 B 4 surfactant mixture. The mixed CMC of the binary combinations falls between those of constituent surfactants. To explain the simulation results, theoretical models like Clint, Rubingh, and Maeda have been used to evaluate the interaction parameter, micellar composition, activity coefficients and the free energies of micellization. By increasing the overall composition until it reaches 0.5, all these parameters indicate non-ideal behavior and synergistic interactions between the surfactants, which is explained in terms of reduction of repulsion between head groups of T 3 H 1 S 2 H 1 T 3 due to the presence of conventional surfactants. At higher ratios, the formation of the aggregations would be harder due to the higher concentration of A 4 B 4 .

Water whitening resistance of pressure-sensitive adhesives obtained from high solids content acrylic dispersions is studied. The effect of the pH and surfactant system on the water whitening of the final films is investigated. The pH used throughout the polymerization process and the pH at which the final latex is adjusted just before the application have a substantial influence on the water whitening resistance. The performance of films obtained from latexes stabilized using conventional surfactant is compared to that of latexes stabilized using polymerizable surfactant or polymerizable stabilizer. In the films containing the conventional anionic surfactant, the water whitening phenomenon is affected by two counteracting mechanisms: latex stability and excess of surfactant in the aqueous phase. However, when polymerizable surfactants or stabilizer are used, due to their incorporation into the polymer backbone, no effect of the surfactant excess is observed leading to films with superior performance increasing their concentration.

Acute respiratory distress syndrome (ARDS) is a pulmonary disorder associated with alterations to the pulmonary surfactant system. Recent studies showed that supra-physiological levels of cholesterol in surfactant contribute to impaired function. Since cholesterol is incorporated into surfactant within the alveolar type II cells which derives its cholesterol from serum, it was hypothesized that serum hypercholesterolemia would predispose the host to the development of lung injury due to alterations of cholesterol content in the surfactant system. Wistar rats were randomized to a standard lab diet or a high cholesterol diet for 17–20 days. Animals were then exposed to one of three models of lung injury: i) acid aspiration ii) ventilation induced lung injury, and iii) surfactant depletion. Following physiological monitoring, lungs were lavaged to obtain and analyze the surfactant system. The physiological results showed there was no effect of the high cholesterol diet on the severity of lung injury in any of the three models of injury. There was also no effect of the diet on surfactant cholesterol composition. Rats fed a high cholesterol diet had a significant impairment in surface tension reducing capabilities of isolated surfactant compared to those fed a standard diet exposed to the surfactant depletion injury. In addition, only rats that were exposed to ventilation induced lung injury had elevated levels of surfactant associated cholesterol compared to non-injured rats. It is concluded that serum hypercholesterolemia does not predispose rats to altered surfactant cholesterol composition or to lung injury. Elevated cholesterol within surfactant may be a marker for ventilation induced lung damage., Graphical abstract fx1, Highlights • Hypercholesterolemia in rats did not alter the susceptibility to lung injury. • Elevated cholesterol within surfactant is observed in ventilation induced lung injury. • Increases in surfactant-associated cholesterol depend on the type of lung injury.

Gravitational drainage from thin vertical surfactant solution films and gravitational drainage in a settler column are used to study the behavior of foams based on two-surfactant mixtures. Namely, solutions of the anionic sodium dodecyl sulfate (SDS) and nonionic superspreader SILWET L-77, and their mixtures at different mixing ratios, are studied. It is shown, for the first time, that solutions having a longer lifetime in the vertical film drainage process also possess a higher foamability. An additional and unexpected unique result is that when using a mixed surfactant system, the foamability can be much greater than the foamabilities of the individual components.

Hydroxyl sulfobetaines with hexadecyl-, octadecyl-hydrophobic chain and an industrial product hydroxyl sulfobetaine were synthesized from analytical-grade and industrial-grade tertiary amine, respectively. The dilational properties and surface tension of the three surfactants at the water-air interface were investigated by drop shape analysis and ring method. The influences of oscillating frequency and bulk concentration on dilational properties were explored. The experimental results show that the dilational module of octadecyl-hydroxyl sulfobetaine was higher than hexadecyl hydroxyl sulfobetaine and the dilational elastic component of the three surfactants were higher than dilational viscous component. Furthermore, the dilational elastic component of mixed surfactant system shows two maxima in a lower concentration than that of single surfactant system. As a result, the surface tension of mixed surfactant system reaches to minimum value in a lower concentration compared with single surfactant system. Th...

A reverse micellar was modified by combining the anionic AOT and zwitterionic lauryl sulfobetaine surfactant for the extraction of erythromycin was proposed for the first time as a new approach for antibiotic extraction. The stability of the mixed reverse micelle was evaluated in terms of the critical micelle concentration (CMC) using the Wilhelmy Ring method, as well as the thermodynamic properties prior to extraction. The effect of parameters such as AOT concentration, lauryl sulfobetaine fraction and pH of the aqueous phase was investigated during forward extraction. Isopropanol volume percent (%), NaCl concentration, and pH of aqueous phase were investigated during backward extraction. The thermodynamic analysis confirmed the stability of the mixed AOT/lauryl sulfobetaine reverse micelle with a positive synergistic effect. The surface activity was enhanced, by which the CMC of the mixed reverse micelle was significantly lowered, ranging from 0.7 to 5.7 g/L. The overall thermodynamic data comprising ΔG m (between -15.44 to -20.24 kJ/mol), ΔG ads (between -27.03 to -28.97 kJ/mol), and ΔG o ex (range between -0.39 to 8.87 kJ/mol) are affirmative that micellization was spontaneous. Erythromycin was also found to be interfacially active at all tested condition. The highest erythromycin solubilisation (94.2%) was achieved, even with low AOT surfactant (60.0 g/L) which reflects the synergy between AOT and lauryl sulfobetaine. In addition, in the absence of isopropanol, erythromycin was found to be successfully recovered during the backward extraction. However, isopropanol is still considered as a recovery booster which enables higher erythromycin recovery.

In order to study the synergism between alkybenzene sulfonate and alkybenzene sulfonate, five di-n-alkylbenzene sulfonates were used and the interfacial tensions of single sulfonates and their binary mixtures against a series of alkane homologues were measured. The effects of hydrophilic-lipophilic abilities of sulfonates and mixing ratio on synergism were discussed. It is revealed that the synergistic mechanism derives from the amelioration of the hydrophilic-lipophilic ability of the surfactant system, and the method to achieve synergism is adding the hydrophilic alkybenzene sulfonate to the lipophilic alkylbenzene sulfonate, and ultralow interfacial tensions can be obtained in proper mixing ratios. The results are useful for enhanced oil recovery.

Dissipative particle dynamics is used to simulate the oil/water/surfactant system in the absence and presence of polymer. Structural properties, interfacial properties, and their dependence on the surfactant concentration, polymer concentration and oil/water ratio were investigated. The snapshots illustrate the variation of the structure of oil/water/surfactant system. In the presence of polymer, the interface is supersaturated at a lower surfactant concentration. The end-to-end distance increases with surfactant concentration and polymer chains but shows weak dependence on the oil/water ratio. The peak of density grows higher with surfactant concentration, but it is not affected by oil/water ratio. The density profiles of polymer grow higher with polymer chains, indicating that most of the polymer chains stay at the interface for stability. Interfacial thickness shows an adsorption of polymer/surfactant complexes at the interface, where the polymer is in an extended conformation at the interface. The for...

Nanoemulsions with very high stability can be created by ultrasonication using a rich variety of surfactants, oils, and solution conditions. Multicompartments within a nanoemulsion droplet can also be created via a carefully chosen surfactant system. We will show in this paper that silica templating of a nanoemulsion system results in compartmentalized hollow silica nanospheres (HSN) of sub-100 nm size under neutral pH conditions. The system consists of water, cetyltrimethylammonium bromide (CTAB), tetraethyl orthosilicate, n-hexadecane, n-octane, and n-hexanol. Two types of HSN can be obtained by manipulating the formulation; one is named single-compartment HSN (SC-HSN), where the HSN encapsulate a single water-in-oil droplet; the other is multiple-compartment HSN (MC-HSN), where the HSN encapsulate multiple smaller HSN. Using a high concentration of CTAB, we obtained a transparent solution of narrow size-distributed ultrasmall HSN (US-HSN) with a diameter of 12 nm. Parameters involved in the nanoemulsio...

The search for stable vesicular structures is a long-standing topic of research because of the usefulness of these structures and the scarcity of surfactant systems that spontaneously form vesicles in true thermodynamic equilibrium. We report the first experimental evidence of spontaneous formation of vesicles for a pure cationic double tail surfactant (didodecyldimethylammonium bromide, DDAB) in a protic ionic liquid (ethylammonium nitrate, EAN). Using small and ultra-small angle neutron scattering, rheology and bright field microscopy, we identify the coexistence of two vesicle containing phases in compositions ranging from 2 to 68 wt %. A low density highly viscous solution containing giant vesicles (D ? 30 ?m) and a sponge (L3) phase coexists with a dilute high density phase containing large vesicles (D ? 2.5 ?m). Vesicles form spontaneously via different thermodynamic routes, with the same size distribution, which strongly supports that they exist in a true thermodynamic equilibrium. The formation of equilibrium vesicles and the L3 phase is facilitated by ion exchange between the cationic surfactant and the ionic liquid, as well as the strength of the solvophobic effect in the protic ionic liquid. � 2012 American Chemical Society.

Control of EOF in microfluidic devices is essential in applications such as protein/DNA sizing and high-throughput drug screening. With the growing popularity of poly(methyl methacrylate) (PMMA) as the substrate for polymeric-based microfludics, it is important to understand the effect of surfactants on EOF in these devices. In this article, we present an extensive investigation exploring changes in EOF rate induced by SDS, polyoxyethylene lauryl ether (Brij35) and CTAB in PMMA microfluidic capillaries. In a standard protein buffer (Tris-Glycine), PMMA capillaries exhibited a cathodic EOF with measured mobility of 1.54 ± 0.1 (× 10⁻⁴ cm²/V.s). In the presence of surfactant below a critical concentration, EOF was independent of surfactant concentration. At high concentrations of surfactants, the electroosmotic mobility was found to linearly increase/decrease as the logarithm of concentration before reaching a constant value. With SDS, the EOF increased by 257% (compared to buffer), while it was decreased by 238% with CTAB. In the case of Brij35, the electroosmotic mobility was reduced by 70%. In a binary surfactant system of SDS/CTAB and SDS/Brij35, addition of oppositely charged CTAB reduced the SDS-induced EOF more effectively compared to nonionic Brij35. We propose possible mechanisms that explain the observed changes in EOF and zeta potential values. Use of neutral polymer coatings in combination with SDS resulted in 50% reduction in the electroosmotic mobility with 0.1% hydroxypropyl methyl cellulose (HPMC), while including 2% poly (N,N-dimethylacrylamide) (PDMA) had no effect. These results will potentially contribute to the development of PMMA-based microfluidic devices.

The enantiopure multi-functional anti Alzheimer’s drug, Ladostigil (TV3326), was prepared by using asymmetric transfer hydrogenation (ATH) as a key step catalyzed by Ru–Cs-DPEN in an HCOONa–H 2 O–surfactant system. Good chemical yields with high enantiomeric excess were obtained and the catalyst could be recycled another five times.

Experimental studies have been conducted to explore the interfacial tensions in an acid-free oil/alkali/surfactant system, and sodium hydroxide is used as the alkali chemical. The influences of salt and alkali on the interfacial activity of oil/surfactant systems were studied by the measurement of interfacial tensions and partition coefficients. The results showed that in an appropriate concentration range, an ultra-low interfacial tension could be obtained in the acid-free oil/alkali/surfactant system, and compared with the salt; the function of alkali for lowering interfacial tensions and improving partition coefficients is more significant.

This paper describes a new synthesis and separation method of nanoparticles (NPs) using a non-toxic, non-ionic surfactant systems. The purification steps did not use ethanol or acetone. Results indicate that the wild type bovine Carbonic Anhydrase (CA) activity was enhanced almost 4 times more than the CA encapsulated NPs fabricated by the traditional method. The NPs have are more hydrophilic and also have a higher zeta potential. The well dispersed CA PAA NPs with of 10-30 nm in diameter were obtained. This work also demonstrates a universal method for immobilizing fragile biomacromolecules in NP carriers for biomedical applications.

To function lipophilic drug Azithromycin (AZM) as ophthalmic preparation, Azithromycin-loaded Nanostructured Lipid Carriers (AZM-NLC) were prepared by High Pressure Homogenization (HPH), and its stability was analyzed afterwards. Well-dissolved lipids of Azithromycin were selected, how the ratio of surfactants to lipids influenced the preparation of AZM-NLC was studied, and mature surfactant system was chosen. The optimized ratio of lipid carriers to emulsifiers [ polyoxyethylene (40) stearate - Poloxamer188 (7:3)] in this study was 1:6, and the final drug-capacity rate was 0.5%. Obtained by photon correlation spectroscopy, the mean particle size of AZM-NLC was 76±2 nm. The results showed that AZM-NLC had kept stable for 15 days, and mean particle size increased to 83 nm after four months.

Emulsions stand among the most important multiphase fluids, exhibiting various complicated phenomenon. To understand the process of emulsification, the Taylor equation has been extended to incorporate the parameters that depend on molecular mass of oil and their contents and the amount of surfactant added. To test the validity of the proposed equations, four well-defined short chain (n-hexane, n-heptane, n-decane, and kerosene) oils were emulsified in water and the results were compared with the experimental ones. It has been concluded that the extended Taylor equation worked well, even in the presence of surfactant. The quality of the emulsion defined and discussed in terms of size and number of droplets was best near CMC of the surfactant used. A relationship has also been derived between CMC of surfactant and its distribution coefficient, which allows the exact value of one parameter to be determined if other is known.

A simple hydrothermal synthesis method was reported for the preparation of various hematite hierarchical structures in a dual-surfactant system, such as stalactite-like, cluster-like and coral-like and so on. The mechanism of formation was studied by adjusting the experimental parameters, and it was found that both oleate and citrate played important roles in the process. Citrate is believed to act as an “etching” reagent in our experiment. The samples obtained were dispersed in a water–hexane mixture to study their surface nature by considering the difference in the lypohydrophilic properties of the oleate and citrate groups. Meanwhile, study of their magnetic properties determined that the oleate and citrate played similar roles in influencing a reductive reaction to convert Fe3+ to Fe2+.

Highly ordered small pore mesoporous silicas were synthesized by using a mixture of surfactants as a template. The surfactant system comprises short-chain cationic surfactant (decyltrimethylammoniu...

With the aid of pH variation, direct transformation of a "1-1" cationic-anionic surfactant pair to a "1-2" cationic-anionic surfactant pair was attained in the system of cetyltrimethylammonium bromide and n-decylphosphoric acid. Owing to the transformation of a "1-1" pair to a "1-2" pair, diverse microstructures and peculiar phase behavior in this cationic-anionic surfactant mixture was obtained at different pH. It is proposed that pH can be manipulated for effectively tailoring the self-assembled organization in this cationic-anionic surfactant system, including spherical micelle, wormlike micelle, vesicle, and lamellar structure. In contrast to the conventional "1-1" surfactant pair, the "1-2" cationic-anionic surfactant pair exhibits unexpectedly weak aggregating ability. It is suggested that the hydrated volume of surfactant headgroup should be taken into consideration to better elucidate the self-assembly behavior of these "1-2" cationic-anionic surfactant mixtures.

The effect of temperature on the interfacial tension between gemini surfactant solution and crude oil is investigated in this paper. The interfacial tension is measured by the spinning drop interfacial tension-meter of Texas-500c. For surfactants 14-4-14 and 16-4-16, the interfacial tensions are very sensitive to temperature and undergo minima with the increase of the temperature. Temperature has also an effect on the dynamic interfacial tension, i.e. increasing the temperature can shorten the time needed for an interfacial tension to reach equilibrium. However, for a mixing surfactant system, the effect of temperature on the interfacial tension between oil and surfactant solution is not remarkable because of synergism.

There are numerous pulmonary conditions in which qualitative or quantitative anomalies of the surfactant system have been demonstrated. In premature newborns with immature lungs, a functional deficit in surfactant is the main physiopathologic mechanism of the neonatal respiratory distress syndrome (RDS). Since the landmark pilot study of Fujiwara, published more than 20 years ago, the efficacy of exogenous surfactant for the treatment of neonatal RDS has been established by numerous controlled studies and meta-analyses. Enlightened by a growing insight into both the structure and function of the different surfactant components, a new generation of synthetic surfactants has been developed. Various complementary approaches have confirmed the fundamental role of the two hydrophobic proteins, SP-B and SP-C, in the surfactant system, thus opening the way to the design of analogues, either by chemical synthesis or expression in a prokaryotic system. An example of these peptide-containing synthetic surfactant preparations, lucinactant (Surfaxin), has been recently tested in comparison to a synthetic surfactant that does not contain protein as well as to animal derived surfactant preparations. Major clinical outcomes between lucinactant and animal-derived surfactant preparations were fund similar in two randomized controlled trials, opening the way to a new generation of synthetic surfactants in the near future.

Surfactant mixtures, consisting of commercially available zwitterionic and anionic surfactants, have been formulated at low-pH condition to obtain ultra-low interfacial tension (IFT). The surfactant systems show good interfacial performance during IFT measurements and subsequent phase behavior tests. The ultralow IFT (magnitude of 10-3 dynes/cm) is reached by formulating a mixed surfactant system that utilizes the synergism principle between a zwitterionic surfactant with amphoteric quality (amine oxide) and various anionic surfactants. Over 40 formulas with various surfactant species, surfactant ratio, pH, and salinity were screened. Screening process for the surfactant mixtures was based on IFT measurement using spinning drop tensiometer and qualitative assessment of solubility, followed by phase behavior tests. All the tests were done using dead crude oil sample and under low surfactant concentration (0.3 – 0.5 weight percent). Possible applications of this surfactant system, such as alkali-free chemical flooding and CO2-foam flooding, will be discussed.

Foamability and foam stability, emulsifying power, surface tension, and interfacial tension were investigated for different ratios of binary surfactant system of Arlacel‐165 (glyceryl stearate (and) PEG‐100 stearate) and Myrj‐59 (polyoxyethylene 100 stearate). Among all the ratios tested for their foaming power and foamabilty, the ratios 8:2, 5:5, 4:6, 2:8, and 1:9 of Arlacel‐165 and Myrj‐59 showed the best results. At these ratios, the foaming power and foamability was found to be 100%. The surfactants having foam stability more than 50% can be considered as metastable and those less than 50% are considered as low‐stability foams. In case of surface tension and interfacial tension property measurements, 8:2 and 9:1 showed the best results. At 8:2 and 9:1 of Arlacel‐165 and Myrj‐59, the surface tension was found to be 37.7 dynes/cm and 1.33 dynes/cm respectively at 30°C ambient temperature. Also, 7:3 of this binary mixture was found to exhibit the best emulsifying power among all the ratios tested. At 30°...

International audience; The influence of the chemical structure of styrene/butyl acrylate latexes on some properties of ordinary Portland cement mortars has been investigated for low fractions of polymer with respect to the amount of cement. The structural parameters that were varied included the presence of carboxylic surface changes, the nature of the surfactant system, the molecular weight of the non-ionic emulsifier, and the particle surface coverage. The first part of the study showed that sterically stabilised latexes remain colloidally and chemical stable for several hours in the cement interstitial medium. Moreover, no interaction could be shown between cement and latex components. Then, for a fraction of about 5wt.-% of polymer, no significant influence of the presence of the latex was observed on the end use properties of the mortars. However, it clearly appears that the use of a fraction anionic stabiliser is highly detrimental to the paste the workability, whereas this latter property is improved by the presence of non-ionic surfactant due to steric repulsion forces. Finally, the microstructure analysis confirms that the particles are homogenously dispersed in the mineral matrix and they remain smooth and spherical.