Sorbitan Monooleate Research Articles

Microfluidic Formation of Honeycomb-Patterned Droplets Bounded by Interface Bilayers via Bimodal Molecular Adsorption.

Assembled water-in-oil droplets bounded by lipid bilayers are used in synthetic biology as minimal models of cell tissue. Microfluidic devices successfully generate monodispersed droplets and assemble them via droplet interface bilayesr (DIB) formation. However, a honeycomb pattern of DIB-bounded droplets, similar to epithelial tissues, remains unrealized because the rapid DIB formation between the droplets hinders their ability to form the honeycomb pattern. In this paper, we demonstrate the microfluidic formation of a honeycomb pattern of DIB-bounded droplets using two surfactants with different adsorption rates on the droplet surface. A non-DIB forming surfactant (sorbitan monooleate, Span 80) was mixed with a lipid (1,2-dioleoyl-sn-glycero-3-phosphocholine, PC), whose adsorption rate on the droplet surface and saturated interfacial tension were lower than those of Span 80. By changing the surfactant composition, we established the conditions under which the droplets initially form a honeycomb pattern and subsequently adhere to each other via DIB formation to minimize the interfacial energy. In addition, the reconstituted membrane protein nanopores at the DIBs were able to transport molecules. This new method, using the difference in the adsorption rates of two surfactants, allows the formation of a honeycomb pattern of DIB-bounded droplets in a single step, and thus facilitates research using DIB-bounded droplet assemblies.

Surfactant-assisted doctor-blading-printed FAPbBr3 films for efficient semitransparent perovskite solar cells.

Organic-inorganic hybrid perovskite solar cells have generated wide interest due to the rapid development of their photovoltaic conversion efficiencies. However, the majority of the reported devices have been fabricated via spin coating with a device area of < 1 cm2. In this study, we fabricated a wide-bandgap formamidinium lead bromide (FAPbBr3) film using a cost-effective, high-yielding doctor-blade-coating process. The effects of different surfactants, such as 1-α-phosphatidylcholine, polyoxyethylene sorbitan monooleate, sodium lauryl sulfonate, and hexadecyl trimethyl ammonium bromide, were studied during the printing process. Accompanying the optimization of the blading temperature, crystal sizes of over 10 µm and large-area perovskite films of 5 cm × 5 cm were obtained using this method. The printed FAPbBr3 solar cells exhibited a short-circuit current density of 8.22 mA/cm2, an open-circuit voltage of 1.175 V, and an efficiency of 7.29%. Subsequently, we replaced the gold with silver nanowires as the top electrode to prepare a semitransparent perovskite solar cell with an average transmittance (400-800 nm) of 25.42%, achieving a high-power efficiency of 5.11%. This study demonstrates efficient doctor-blading printing for preparing large-area FAPbBr3 films that possess high potential for applications in building integrated photovoltaics.

Displacement of interfacially-bound monoglyceride crystals in water-in-oil emulsions by a non-ionic surfactant

HypothesisMicron and nano-scale particles are increasingly used to stabilize water-in-oil (W/O) emulsions. Though remarkably stable, the resulting emulsions can be broken by adding low molecular weight surfactants that modify the wettability of the interfacially-adsorbed particles. ExperimentsW/O emulsions were prepared using lipophilic crystals of the monoglyceride glycerol monostearate (GMS), followed by addition of sorbitan monooleate (SMO) at concentrations below and above its critical micelle concentration (CMC). Systematic measurements of interfacial tension and three-phase contact angles, as well as characterization of emulsion sedimentation and microstructure, were used to assess GMS crystal wettability and emulsion destabilization. FindingsGMS crystals formed shells around the dispersed droplets, resulting in emulsions stable against breakdown under quiescent conditions. With SMO concentrations added below CMC, emulsion stability was not significantly affected. At SMO concentrations above CMC, the integrity of the crystalline shell was markedly affected. Notably, the GMS crystals transitioned from preferential oil-wet to water-wet behavior, eventually leading to their diffusion into the droplets. Therefore, in-situ modification of particle wettability at the oil–water interface was responsible for emulsion breakdown. Findings from this study may provide a pathway for the design of particle-stabilized W/O emulsions with controllable breakdown properties for applications such as tailored release of aqueous bioactive compounds.

Retraction of “Investigation of the Effect of Various Additives on the Clouding Behavior and Thermodynamics of Polyoxyethylene (20) Sorbitan Monooleate in Absence and Presence of Ceftriaxone Sodium Trihydrate Drug”

ADVERTISEMENT RETURN TO ISSUEPREVRetractionNEXTORIGINAL ARTICLEThis notice is a retraction.Retraction of “Investigation of the Effect of Various Additives on the Clouding Behavior and Thermodynamics of Polyoxyethylene (20) Sorbitan Monooleate in Absence and Presence of Ceftriaxone Sodium Trihydrate Drug”Marzia RahmanMarzia RahmanMore by Marzia Rahman, Mohammed Abdullah KhanMohammed Abdullah KhanMore by Mohammed Abdullah Khan, Malik Abdul RubMalik Abdul RubMore by Malik Abdul Rub, Md. Anamul Hoque*Md. Anamul HoqueMore by Md. Anamul Hoquehttp://orcid.org/0000-0002-2609-1815, and Abdullah M. AsiriAbdullah M. AsiriMore by Abdullah M. AsiriCite this: J. Chem. Eng. Data 2020, 65, 7, 3754Publication Date (Web):June 23, 2020Publication History Published online23 June 2020Published inissue 9 July 2020https://doi.org/10.1021/acs.jced.0c00542Copyright © 2020 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views454Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (433 KB) Get e-Alerts Get e-Alerts

Antioxidant Effect of Vitamins in Olive Oil Emulsion

In this study, water-in-extra virgin olive oil emulsions were enriched with vitamins. Water-in oil emulsions are heterogeneous systems able to solubilize both hydrophilic and hydrophobic compounds. Thus, hydrophilic vitamin C and lipophilic vitamin E were loaded separately or together in emulsion. A suitable emulsion composition was selected after considering different surfactant (mono and diglycerides of fatty acids, E471; sorbitan monooleate, Span 80; polyoxyethylene sorbitan monooleate, Tween 80) and water concentrations. The most appropriate emulsion, for the high stability, resulted the one containing concentrations of Span 80 1% w/w and water 1% w/w. The antioxidant effect of vitamins in emulsions was studied considering the variation of the peroxide values during storage. The oxidation reaction was slowed down in emulsions containing vitamin C, but it was quickened by the loading of vitamin E for its high concentration. In emulsions containing vitamin E, indeed, the peroxide values were higher than in emulsions prepared in the absence of vitamins or in oil. The antioxidant activity generated by the co-loading of vitamin C and E was very effective to the point that in presence of high amounts of vitamins the peroxide values did not change in about 40 days of storage, due to the vitamin E regeneration by vitamin C.

Abstract withdrawn: Formation and Oxidation Stability of Tea Polyphenols-Loaded W/O Microemulsion with Eucommia Ulmoides Oliver Seed Oil as an Alternative to α-linolenic Acid.

[This retracts the article DOI: 10.1093/cdn/nzab071.].

Is the combination of two particles with different degrees of hydrophobicity an alternative method for tuning the average particle hydrophobicity?

A systematic investigation into the equivalence between two methods of tuning average particle hydrophobicity: varying the extent of chemical anchoring of alkyl chains onto the surface of a single particle (chemical method) and mixing particles of different hydrophobicity (mechanical method), in stabilization of highly concentrated water-in-oil emulsions with an overcooled dispersed phase, in the presence of low-molecular-weight conventional surfactant (Sorbitan Monooleate - SMO), has been made. Two single particles with different degrees of surface treatments, expressed in terms of hydrophobicity index (HI), HI = 0.97 and HI = 1.34 were used (chemical method). Equivalent twin mixtures were produced by using specific ratios between fumed silica nanoparticles of HI = 0.60, 1.34 and 3 (mechanical method): HI = 0.97: (HI = 1.34)/(HI = 0.60) = 50/50 or (HI = 3)/(HI = 0.60) = 15/85 and HI = 1.34: (HI = 3)/(HI = 0.60) = 31/69. Each single or twin mixture was combined with different amounts of SMO in the range of 0–10 wt%.Rheology of oil dispersions with no surfactant demonstrated that the mechanical method is quantitatively equivalent to the chemical method, in agreement with previous works where different techniques were used. Conversely to the case without surfactant, it has been found that the influence of such factors as surfactant-to-particle ratio or average particle HI on stability and rheology of fresh, as well as aged, oil dispersions on emulsion refinement kinetics, emulsion stability against the crystallization of the inner phase is strongly dependant on the method used to tune the particle hydrophobicity. Regardless of the SMO/particle ratio, a drastic change in the rigidity of flocs in aged oil dispersions and emulsion properties occurs when single particles are replaced by their equivalent twin mixtures in the presence of a surfactant. Interestingly, homogeneous nucleation within the droplets is the dominant mechanism of crystallization of nitrate salts in the super-cooled droplets stabilized with single particles (chemical method). On the other hand, heterogeneous nucleation catalysed at the surface of droplets was found to be the dominating mechanism of crystallization of nitrate salts in the super-cooled droplets for equivalent binary mixtures (mechanical method).

Stability and characterization studies of Span 80 niosomes modified with CTAB in the presence of NaCl

This work reports the study of surface and aggregation properties of formulations containing mixed niosomes of the non-ionic surfactant sorbitan monooleate (Span 80) and the cationic surfactant cetyltrimethylammonium bromide (CTAB), in concentrations of 20 and 4 mol/m3, respectively, in salt-free water and in the presence of NaCl (20, 50 and 80 mol/m3). The aim of this work was the formulation of stable Span 80 and CTAB mixed niosomes with low surfactant concentration. The mixed niosomes were prepared by ultrasonication and their properties (surface tension, particle size distribution, ζ-potential, stability over time and morphology) were measured using different techniques. Data were analyzed and compared with those of the individual surfactants. Experimental results show that the addition of salt decreased the critical micelle concentration (CMC) and the surface tension of the surfactant dispersions with relation to their free-salt formulations. The presence of CTAB in the mixed niosome bilayer decreased the particle size and increased the stability of the mixed niosomes in all the formulations studied, compared with those of single Span 80. Synergism between both surfactants was obtained in the formation of niosome bilayers for formulations in pure water and with 20 and 50 mol/m3 of salt, while antagonism was observed in that of 80 mol/m3 NaCl. These results may allow the use of CTAB adsorbed on mixed niosomes in industrial applications, taking advantage of its antiseptic and antibacterial properties and solving the limitation imposed by its high Krafft temperature.

Preparation of Conductive Silver Films from Electrophoretic Concentrates Stabilized with Sorbitan Monooleate and Sodium Bis(2-Ethylhexyl)Sulfosuccinate in n-Decane

A high-productivity method has been proposed for the synthesis of silver nanoparticles with sizes of 11.2 ± 0.3 nm in water-in-oil emulsions stabilized with sorbitan monooleate (Span 80). It has been shown that, in the course of the synthesis, initial reagents are transferred from emulsion droplets into Span 80 micelles. As a result, nanoparticles are formed due to the intermicellar exchange by the mechanism of micellar (microemulsion) synthesis. The addition of an anionic surfactant, sodium bis(2-ethylhexyl)sulfosuccinate (AOT) provides the nanoparticle surface with a negative charge (ζ-potential is –50.0 mV). This has made it possible to employ nonaqueous electrophoresis for obtaining a liquid concentrate, the evaporation of which has yielded a dry Ag/Span 80/AOT composite. Silver contents in the concentrate and composite are 30 and 70%, respectively. X-ray diffraction and thermal analysis methods have been used to study the composite thermolysis, which results in the formation of conductive silver films (0.43 Ω/sq).

Characterization of self-assembled silver nanoparticle ink based on nanoemulsion method.

A well-dispersed self-assembled silver nanoparticles (AgNPs) ink with high purity was synthesized via AgNO3 emulsion prepared by blending an AgNO3 aqueous solution and a liquid paraffin solution of both polyoxyethylene (20) sorbitan monooleate (Tween 80) and sorbitan monooleate (Span 80). The ink remained as an emulsion at low temperatures; however, it produced AgNPs after sintering at about 60°C and showed a high stability at nanoscale sizes (with diameters ranging 8.6–13.4 nm) and a high conductivity. During the whole procedure, Tween 80 acted as a surfactant, reductant and stabilizer. Presumably, Tween 80 underwent an autoxidation process, where a free radical of an α-carbon of ether oxygen was formed by hydrogen abstraction. The mean diameter of emulsion droplets could be reduced by decreasing water content and increasing the ratio of surfactant and concentration of AgNO3 aqueous solution. Consequently, the thermogravimetric analysis and X-ray diffraction result clarified the purity of the produced Ag0. Dynamic light scattering and ultraviolet-visible spectroscopy clarified that an increased concentration of AgNO3 decreased the particle size.

Selective extraction and recovery of polyphenols from palm oil mill sterilization condensate using emulsion liquid membrane process.

Polluted sterilization condensate discharged from palm oil mill may contain polyphenols that are rich in the antioxidant property. Emulsion liquid membrane (ELM) process is a promising method for polyphenol recovery due to its several attractive features such as high selectivity, simple operation, and low energy consumption. In this study, the condensate was characterized to determine its total phenolic content (TPC), ionic elements, and pH. ELM formulation containing tributylphosphate (TBP) as a carrier, kerosene as a diluent, sorbitan monooleate (Span 80) as a surfactant, and sodium hydroxide (NaOH) as a stripping agent was developed. The results show that sterilization condensate contains 700-1500mg GAE/L of TPC. During the ELM process, more than 91% of extraction with 83% recovery and 8.3 enrichment were achieved at the favorable condition of 0.1M TBP, external phase pH5, 1M NaOH, 1:5 treat ratio, 5% v/v of octanol as a modifier, and 100mg GAE/L external phase concentrations. Thus, ELM offers a potential alternative technology to extract and recover polyphenols from palm oil mill sterilization condensate while contributing to sustainable production. Graphical abstract Extraction of polyphenols from palm oil mill sterilization condensate using ELM process.

Formation and stability of Eucommia ulmoides Oliver seed oil-loaded inverse microemulsion formed by food-grade ingredients and its antioxidant activities.

Eucommia ulmoides Oliver seed oil (E.u oil) as a functional oil is rich in many natural active components such as α-linolenic acid (56% to 63%), vitamin E, aucubin, and so on. In this study, water-in-oil (W/O) microemulsions composed of Eucommia ulmoides Oliver seed oil, distilled water, a blend of Sorbitan monooleate 80 (Span 80) and Polysorbate (20) sorbitan monooleate (Tween 80), and propylene glycol were prepared for improving the compatibility of Eucommia ulmoides Oliver seed oil. Pseudoternary phase diagrams were built to illustrate the phase behavior of the microemulsions, based on hydrophilic-lipophilic balance values, cosurfactant type, the proportion of cosurfactant, and the changing environmental stress. Dynamic light scattering, transmission electron microscopy, and electrical conductivity measurements were performed to characterize the microstructural aspects. The optimum process conditions at which the Eucommia ulmoides Oliver seed oil-loaded microemulsion had good tolerance to pH and salinity were: Propylene glycol served as cosurfactant, water-Propylene glycol, and Span 80-Tween 80 ratios separately kept constant at 1:1 and 6:4. These microemulsions with narrow size distribution, nanoscale particle size (below 60nm), transparent appearance had a wide range of oil phase content and free-radical scavenging capacity toward DPPH and ABTS radicals with half-maximal inhibitory concentration (IC50 ) values of 49.20 and 33.43mg/mL, respectively. PRACTICAL APPLICATION: This nanostructure, environmental stability, and antioxidant activity of microemulsions containing Eucommia ulmoides Oliver seed oil is a potential delivery system as an alternative to α-linolenic acid and can be used for the delivery of peptides, proteins, antioxidants, and water-soluble nutrients.

Protective effects of five surfactants on cellulase in the saccharification of corn stover based on the impeded Michaelis-Menten model

Protective effects of five surfactants were investigated relative to the saccharification of lignocellulose using the impeded Michaelis-Menten model (IMM). The yield of total reducing sugar (Ytrs) and cellulase activity were indexed as the effect of surfactant. The IMM was used to fit the correlation between Ytrs and reaction time to obtain the index (Kobs,0) reflecting the accessibility between cellulose and lignocellulose and the comprehensive index (Ki) reflecting cellulase inactivation and non-specific site adsorption. Results showed that the strongest protective effect was found from polyoxyethylene (80) sorbitan monooleate, followed by rhamnolipid. The surfactants protected cellulase from inactivation and nonspecific site adsorption of lignocellulose in the saccharification, leading to enhanced cellulase activity, especially with respect to carboxymethyl cellulase (CMCase) and filter paper enzyme (FPase) activities. The maximum Ytrs was obtained when the CMCase activity was 136.2 U/mL, while the FPase and β-glucosidase activities should be as high and low as possible, respectively, under the optimized condition. These findings lay the foundation for improving the saccharification efficiency of cellulase and reducing the cost of saccharification of biomass cellulose.

Biotransformation and Degradation Pathway of Pyrene by Filamentous Soil Fungus Trichoderma sp. F03

Pyrene, a toxic four-benzene-ring that persists in the ecosystem, is highly resistant to degradation. The goal of the research is to screen, isolate, and identify pyrene-degrading filamentous fungi via the molecular biological identification method. The capabilities of identified isolates in biodegradation and transformation of pyrene were also evaluated. Based on the morphological characterization and sequence alignments, results of neighbor-joining phylogenetic tree from 18S rRNA of F03 revealed that genetic similarity had achieved 99% of homology percentage and identified as Trichoderma sp. Trichoderma sp. F03 was able to degrade pyrene (78%) when culture conditions were set at 100 mg/L initial pyrene concentration in culture medium with pH 5 at 27 °C, the use of glucose as a carbon source and polyethylene glycol sorbitan monooleate as a biosurfactant without agitation. Finally, three metabolites, benzoic acid, 3-hydroxybenzoic acid, and acetic acid, were detected during the pyrene degradation process by using gas chromatography–mass spectrometry (GCMS).

The use of non-ionic surfactants with different Hydrophilic-Lipophilic Balance (HLB) and their effect on flow properties in palm oil biodiesel

The use of surfactants has been known to reduce the interfacial tension between the two fluids. Surfactants have Hydrophilic-Lipophilic Balance (HLB) values that vary depending on their function. Previously, the addition of the Sorbitan Monooleate (SMO) had succeeded in reducing the Cloud Point (CP) by 4.2°C and the Cold Filter Plugging Point (CFPP) by 2°C. In this research, two different types of nonionic surfactants were tried, named the Sorbitan Monolaurate (SML) and the Sorbitan Trioleate (STO), which have HLB values of 8.6 and 1.8, respectively. This research aims to prove whether these surfactants can improve the flow properties of palm oil biodiesel by reducing the interfacial tension. Each surfactant was varied in palm oil biodiesel with a content of 1 and 2% at room temperature (±27°C) for a month with every week observation. Then, it was tested using the flow properties parameters, which are the CP, Pour Point (PP), and CFPP. The FTIR analysis is also carried out to determine the interactions between MG and these surfactants. The addition of 1% SML caused escalation in the CP, PP, and CFPP by 3.2, 3.5, and 6°C, respectively. Meanwhile, the addition of 2% STO caused a reduction in the CP and PP by 0.5 and 1°C, respectively but the CFPP tended to be constant.

Studying Surfactant Effects on Hydrate Crystallization at Oil-Water Interfaces Using a Low-Cost Integrated Modular Peltier Device

We introduce an approach to study the formation and growth of hydrates under the influence of nonionic surfactants. The experimental system includes a temperature regulator, visualization techniques, and inner pressure measurements. The temperature control system contains a low-cost, programmable temperature regulator made with solid-state Peltier components. Along with the temperature control system, we incorporated visualization techniques and internal pressure measurements to study hydrate formation and inhibition in the presence of nonionic surfactants. We studied the hydrate-inhibiting ability of nonionic surfactants (sorbitane monolaurate, sorbitane monooleate, PEG-PPG-PEG, and polyoxyethylenesorbitan tristearate) at low (i.e., 0.1 CMC), medium (i.e., CMC), and high (i.e., 10 CMC) concentrations. Two types of crystals were formed: planar and conical. Planar crystals were formed in plain water and low surfactant concentrations. Conical crystals were formed in high surfactant concentrations. The results of the study show that conical crystals are the most effective in terms of hydrate inhibition. Because conical crystals cannot grow past a certain size, the hydrate growth rate as a conical crystal is slower than the hydrate growth rate as planar crystal. Hence, surfactants that force hydrates to form conical crystals are the most efficient. The goal of the protocol is to provide a detailed description of an experimental system that is capable of investigating the cyclopentane hydrate crystallization process on the surface of a water droplet in the presence of surfactant molecules.

Engineering and Economic Perspective in The Production of Cu Nano

The purpose of this study is to analyze the production of copper nanoparticles (Cu NPs) on an industrial scale in an engineering perspective and economic evaluation perspective. Energy is needed because of various energy related applications. Evaluation of Cu nanoparticle production in an engineering perspective is carried out from the selection of processes that are adapted to industrial scale, calculation of mass balance, to the adjustment of commercially available equipment. Evaluation of production from an economic point of view is done by calculating economic parameters: Gross Profit Margin, Internal Return Rate, Payback Period, Cumulative Net Present Value, Profitability Index, and Break Even Point. Briefly from the production process, we use Copper acetate hydrate (CuAc2.2H2O) (as a source of Cu), Tween 80 (polyoxyethylene-(80)-sorbitan monooleate) and ethylene glycol (as a reducing agent). The engineering viewpoint shows this process is capable of producing Cu nanoparticles which can be used as conductive nanoionic. Economic evaluation determines the process is beneficial, discussing with positive values ​​all economic parameters. However, for some variations this process is not profitable, so economic evaluation is needed.

Anti-Agglomeration Effects of Biodegradable Surfactants from Natural Sources on Natural Gas Hydrate Formation

Kinetic hydrate inhibitors (KHI) and anti-agglomerants (AA) rather than thermodynamic hydrate inhibitors (THI) are often used for flow assurance in pipelines. This is because they require much lower dosages than thermodynamic inhibitors. Although the hydrate-phase equilibria are not affected, KHI and AA prevent the formed hydrate crystals from growing to a bulky state causing pipeline blockage. However, these KHIs might have huge environmental impact due to leakages from the pipelines. In this study, two biodegradable AA candidates from natural sources (that is, lecithin and lanolin) are proposed and their performances are evaluated by comparing them with and without a conventional AA (Span 80, sorbitan monooleate). At 30% and 50% water cut, the addition of AA materials was found to enhance the flow characteristics substantially in pipelines and hardly affected the maximum value of the rotational torque, respectively. Considering the cost-effective and environmental advantages of the suggested AA candidates over a conventional AA such as Span 80, the materials are thought to have potential viability for practical operation of oil and gas pipelines. However, additional investigations will be done to clarify the optimum amounts and the action mechanisms of the suggested AAs.

Thermal decomposition, phase formation and microstructure analysis of surfactant assisted sol-gel derived La0.6Sr0.4CoO3-δ material

A single-phase of perovskite-type oxide material can be prepared at a processing temperature relatively lower than 1000 °C through a sol-gel method. However, it is affected by the nature of chemical additives employed during the synthesis process. In the present work, sol-gel derived lanthanum strontium cobaltite, La0.6Sr0.4CoO3-δ (LSC64) material is prepared using various non-ionic surfactants namely polyoxyethylene (10) oleyl ether (Brij-97), polyoxyethylene octyl phenyl ether (Triton-X-100) and polyoxyethylene (20) sorbitan monooleate (Tween-80). The prepared powders of the LSC material is subsequently subjected to the thermal decomposition, phase formation and microstructure analysis by a thermal gravimetric analyzer, an X-ray diffractometer and a scanning electron microscope (SEM), respectively. The as-synthesized powders are calcined at different temperatures based on the thermal gravimetric analysis results. X-ray diffractometer results reveal that all of the calcined powders consist of more than 90 % perovskite phase of LSC64 and other secondary phases such as cobalt oxide, lanthanum oxide and strontium carbonate. The Brij-97-based and Tween-80-based calcined powders have morphology of typical clump-like network structure, while the Triton-X-100-based calcined powder has morphology of flake-like network structure.

Synthesis and Characterization of Silver Nanoparticles in Reverse Micelles of Nonionic Surfactants and in Their Mixed Micelles with AOT

Stable silver nanoparticles have been obtained in reverse micelles of known and available nonionic surfactants, sorbitan monooleate (Span 80) and tetraethoxylated dodecanol and p-nonylphenol (Brij 30 and Tergitol NP-4, respectively), in n-decane. The obtained nanoparticles have been characterized using a number of physicochemical methods. The stability, hydrodynamic diameter, and electrokinetic potential of the nanoparticles have been studied as depending on the amounts of added water; chloroform; and an anionic surfactant, sodium bis(2-ethylhexyl)sulfosuccinate (AOT). It has been shown that, for different surfactants, AOT should be introduced in different ways to provide the nanoparticles with the electrokinetic potential values sufficient for enhancing their stability and ensuring the possibility of concentrating them by nonaqueous electrophoresis. In the case of Brij 30, it is preferable to introduce AOT after the synthesis as a “charging additive,” while, in the case of Tergitol NP-4, it should be added as a cosurfactant at the stage of the synthesis. The nanoparticles synthesized in Span 80 micelles have a rather high electrokinetic potential even in the absence of the additives. In this case, the use of AOT as a cosurfactant decreases the electrokinetic potential of the nanoparticles, while, being added after the synthesis, it increases the potential.