Synthesis of Cu_2O nanowhiskers with CTAB as a template in water-in-oil microemulsion system

Dispersed cuprite （Cu2O） nanowhiskers were synthesized in a water/butanol/cyclohexane/cetyl trimethyl ammonium bromide （CTAB） water-in-oil microemulsion system at 25℃. The nanowhiskers with a diameter of about 8 am exhibit a well-crystallized one-dimensional （1D） structure over several hundreds nanometers in length and mainly grow along the 〈111〉 direction. However, without CTAB, only cubic and hexagonal bulks are obtained. Without emulsifier, short and thick nanowhiskers can be prepared but they are apt to agglomerate. The possible growth mechanism of Cu2O nanowhiskers is speculated. The surfactant and the microemulsion system are related to the 1D shape formation and the even dispersion of Cu2O nanomaterials, respectively.

Phase behavior of TXs/toluene/water microemulsion systems for solubilization absorption of toluene

Triton Xs （TXs） surfactants/cosurfactant/water/oil （toluene） microemulsion systems for enhancing toluene solubilization were proposed and its potential was investigated for toluene removal from gas stream. The results indicated that TX-100 was superior to other TXs surfactants in removing toluene without cosurfactant. The efficiency of cosurfactants for improving toluene solubilization capacity follows the order： amine 〉 alcohol 〉 acid. According to the factor analysis, the linear cosurfactants are better than the branched ones. The effects of hydrophile-lipophile balance （HLB）, salt （NaCl） concentration and temperature on the formation of microemulsion system were also discussed. The results suggested that the optimum value of HLB was 15, the effect of NaCl concentration on the system was inconspicuous and the lower temperature enhanced the solubilization capacity. Nonionic surfactant-based microemulsions had a significant absorption enhancement for toluene, indicated by as much as 82.72% of toluene in phase composition diagram, which will have a great prospect in air pollution treatment.

Physicochemical Properties and Evaluation of Microemulsion Systems for Transdermal Delivery of Meloxicam

Microemulsion systems, composed of water, isopropyl myristate （IPM）, polyoxyethylene sorbitan trioleate （Tween 85 ）, and ethanol, were investigated as transdermal drug delivery vehicles for a lipophilic model drug（ meloxicam）. The purpose of this study was to investigate the physicochemieal properties of the tested microemulsion and to find the correlation between the physicoehemical properties and the skin permeation rate of the microemulsion. Pseudo-ternary phase diagram of the investigated system at a constant surfactant/cosurfactant mass ratio （ Km = 1 ： 1 ） was constructed by titration at 20℃, and the five fommlations were selected for further research in the o/w microemulsion domains. The values of electrical conductivity and viscosity showed that the selected systems were bicontinuous or non-spherical o/w microemulsion, and the electrical conductivity and viscosity were increased with increasing the content of water. These results suggest that the optimum formulation of microemulsion, containing 0. 375 meloxicam, 5% isopropyl myristate, 25% Tween 85. 25% ethanol, and water, showed the maximum permeation rate. It had a high electrical conductivity, small droplet size, and proper viscocity.

Phase Behavior of Sodium Dodecyl Sulfate-n-Butanol-Kerosene-Water Microemulsion System

Experiments were carried out to investigate the influences of cation from electrolytes and acidity/alkalinity on the phase behavior of sodium dodecyl sulfate-n-butanol-organics-water （with electrolytes） microemulsion sys-tem. The organics used is commercial kerosene. The volume ratio of water to organics is 1︰1. The results show that the type and valence of electrolyte cations are important factors influencing the microemulsion behavior. Biva-lent Ca2＋is more effective than monovalent K＋and Na＋for the formation of Winsor type III and II microemulsion. For electrolytes with the same monovalent cation Na＋, i.e. NaCl and Na2CO3, anions in the electrolyte have some effect. Bivalent anion 23CO - leads to a lower activity of cation Na＋than monovalent anion Cl-. NaOH （or KOH） behaves similar with NaCl （or KCl）. When HCl is used as electrolyte, its acidity plays an important role. Phase in-version of microemulsion from type III （or II） to type I is observed through precipitation of Ca2＋using Na2CO3, neutralization of HCl by NaOH, and addition of water to the system, which releases the oil from the microemulsion.

Investigation of Microemulsion System for Transdermal Drug Delivery of Amphotericin B

In order to solve the drawback of poor bioavailability by the oral route and infusion-related side effect for Amphotericin B（AmB）, microemulsion vehicles composed of isopropyl myristate（IPM）, Tween 80, isopropyl alcohol and water for transdermal delivery of AraB were designed. The pseudo-ternary phase diagrams were constructed by the H2O titration method and the structures of the microemulsion were determined by measuring electrical conductivities（σ）. The diffusion studies of AmB microemulsion were performed via excised rabbit skin on a drug diffusion apparatus. To obtain a high solubization of AmB, three different methods were tested to incorporate AmB into microemulsion. The result suggests adding AmB in the shape of NaOH solution to the O/W blank microemulsion over the phase inversion temperature（PIT） of the emulsifier obtains the maximum drug content（2.96 mg/mL）. The pH value of the system could be adjusted to pH〉8.5 or pH〈5.2, in this range AraB molecules converts from aqueous to the hydrophilic shell of the microemulsion droplets, drug precipitate is no more than 5%, and the formulations were corresponding to the characterizations of microemulsion. At pH 5.14, AmB microemulsion with Km 1：1, O/SC 1：9（mass ratio of oil phase to surfactant/cosurfactant blend）, water content 64.6%, drug content （2.93±0.08） mg/mL, showed the maximum permeation rate （3.255 ±0.64） μg·cm^-2.h^-1 which is stable for a long time.

The Structural Conversion in Microemulsion Systems of C_(12)H_(25)SO_3Na-C_4H_9OH-C_7H_(16)-H_2O

An investigation of the structural conversion in microemulsion system of sodium dodecylsulfonate-butanol-heptane-water was carried out by cyclic voltammetry and conductivity techniques.

Preparation of BaMgAl_(10)O_(17):Eu^(2+) and Its Phase Behavior in Microemulsion System

BaMgAl10O17 ： Eu^2＋ （BAM） was prepared in the microemulsion system and its phase behavior was studied. There exists a small region in the reverse microemulsion system where the dispersed particles are of spherical form. In this way, BAM blue phosphor with good dispersion can be synthesized. The microemulsion phase diagrams of the pseudo-ternary system （Triton X-100/cosuffactant-oil-BAM brine） were first established intuitively by the dilution method. The microstructure of microemulsions was determined through eyeballing, conductance technique, and polar optical microscopy. Its phase behavior is affected by various factors, such as temperature （room temperature, 30, 40 ℃）, oil, surfactants, and cosurfactants in microemulsions. According to the phase diagrams, the microemulsion system of Triton X-100/1-hexanol-hexane-BAM brine was chosen to prepare the precursor. The BAM phosphor can be obtained via sintering the precursor at a comparatively low temperature. The phosphors were characterized by XRD and vacuum ultraviolet （VUV） spectra.

Imbibition mechanisms of high temperature resistant microemulsion system in ultra-low permeability and tight reservoirs

Lower-phase microemulsions with core-shell structure were prepared by microemulsion dilution method.The high temperature resistant systems were screened and the performance evaluation experiments were conducted to clarify the spontaneous imbibition mechanisms in ultra-low permeability and tight oil reservoirs,and to direct the field microfracture huff and puff test of oil well.The microemulsion system(O-ME)with cationic-nonionic surfactant as hydrophilic shell,No.3 white oil as oil phase core has the highest imbibition recovery;its spontaneous imbibition mechanisms include:the ultra-low interfacial tension and wettability reversal significantly reduce oil adhesion work to improve oil displacement efficiency,the nanoscale“core-shell structure”formed can easily enter micro-nano pores and throats to expand the swept volume,in addition,the remarkable effect of dispersing and solubilizing crude oil can improve the mobility of crude oil.Based on the experimental results,a microfracture huff and puff test of O-ME was carried out in Well YBD43-X506 of Shengli Oilfield.After being treated,the well had a significant increase of daily fluid production to 5 tons from 1.4 tons,and an increase of daily oil production to 2.7 tons from 1.0 ton before treatment.

An Osmotic Pressure Equation of Uncharged Micelle and Oil/Water Microemulsion Systems

1 INTRODUCTIONMicroemulsion and micelle systems are wide-spread in the industry and agriculture applications,e.g.the petroleum exploitation,food industry chemical engineering and biological engineering,but so far,their properties are still not very well understood.Both micelle and microemulsion systems are dispersed systems and consist of the aggregationsof the surfactant.The difference between them is that there is dispered liquid phase in the coreof the aggregation in the case of the microemulsion,but in the micelle there is not any

Extraction of samarium by NaOL-pentanol-hetpane-NaNO3 winsor Ⅱ microemulsion systems

The influence of the concentration of sodium oleate （NaOL） and pentanol on the water uptake of microemulsion was stuied. The effect of the concentraction of NaOL and pentanol on the extraction yield of samarium was investigated. The result shows that the extraction and concentration of samarium is effective under well-defined conditions utilizing Winsor Ⅱ microemulsioin systems. The FT-IR spectra and conductivity research may indicate that stable hydrophobic chelate complexes were produced after the extraction of Sm（Ⅲ） by NaOL micromulsion systems.

Intranasal Delivery of Two Benzodiazepines, Midazolam and Diazepam, by a Microemulsion System

Nasal application of benzodiazepines might be an alternative to intravenous administration in acute clinical situations such as seizures emergencies. However, irritation and pain as well as symptoms like teary eyes, dizziness, discomfort, nasal drainage and bad taste usually accompany subject received midazolam and diazepam via the nasal route. The purpose of this study was to evaluate the use of a new alcohol-free microemulsion system as a carrier for diazepam or midazolam given intranasally. Midazolam (base) or diazepam was solubilized in the microemulsion to obtain a high drug concentration of 25 mg/g (2.5% by weight), to provide 2.5 mg drug in 100 μl spray (d ≈ 1.00 g/ml). The nasal absorption of both drugs from the same microemulsion formulation (containing 20% aqueous phase) was found to be fairly rapid after administration of 0.4 mg/kg to rabbits. The absolute bioavailability of diazepam after intranasal administration using this formulation was 33.45% ± 12.36% and the tmax was 18.33 ± 23.09 min, which was twice longer than the tmax obtained after midazolam administration, 9.25 ± 6.75 min. The pharmacokinetic parameters of midazolam in W/O (20% water) microemulsion and their comparison with midazolam in O/W (50% water) microemulsion have shown that both formulations resulted in a relatively short time to reach the peak plasma level (tmax), that is, 9.25 ± 6.75 min and 6.75 ± 5.67 min, respectively. However, the peak plasma levels (Cmax) and the absolute bioavailability (FA) of midazolam were significantly higher after administration of the W/O formulation than those obtained after application of O/W formulation, i.e., 46.62 ± 17.38 μg/ml vs. 15.44 ± 4.00 μg/ml, and 35.19% ± 11.83% vs. 19.83% ± 16.32%, respectively. Our results suggest that the new microemulsion system may be useful for getting rapid-onset of midazolam and diazepam following intranasal administration, resulting in reasonable peak plasma levels and bioavailability, but most importantly, providing a high measure of tolerability and comfort.

Synthesis of Crystallized BaWO₄Nanorods in a Microemulsion System

BaWO4 nanorods have been successfully synthesized in w/o microemulsion system containing barium ions via a simple reaction between Ba2+ and . The BaWO4 Nanorods were characterized by XRD, TEM, and SEM, respectively. Results showed that the solvents composition—volume ratio of 4-dioxane and distilled water—played the key role in the formation of BaWO4 Nanorods. Furthermore, the strong vibration at 925 cm﹣1 on its Raman spectrum indicated that the BaWO4 nanorods is good at stimulating Raman scattering in transient and steady-state, making it as a promising candidate material for laser with self-raman conversion of radiation inside the active medium.

Percutaneous absorption and brain distribution facilitation of borneol on tetramethylpyrazine in a microemulsion-based transdermal therapeutic system

In this study, we show that the percutaneous absorption and brain distribution of tetramethylpyrazine(TMP) is enhanced when combined with borneol(BN) in a microemulsionbased transdermal therapeutic system(ME-TTS). The formulation of the TMP and BN microemulsion(TEM-BN-ME) was optimized in skin permeation studies in vitro following a uniform experimental design. Male Sprague-Dawley rats were used for the in vivo pharmacokinetic and tissue distribution studies of TMP-BN-ME-TTS. In the pharmacokinetic study, the TMP-BN-ME-TTS treated rats had significantly higher( P < 0.05) C max and AUC of TMP than the TMP-ME-TTS treated rats, indicating that BN improves the rate and extent of TMP percutaneous absorption. In the tissue distribution study, the AUC of TMP in brain was significantly higher in the TMP-BN-ME-TTS group( P < 0.05), indicating that BN facilitates the distribution of TMP in brain. In summary, BN enhanced the percutaneous absorption and brain distribution of TMP in a microemulsion-based transdermal therapeutic system.

Study on Osmotic Pressure and Liquid-Liquid Equilibria for Micelle, Colloid and Microemulsion Systems by Yukawa Potential

An equation of state (EOS) was established to study the osmotic pressure and liquid-liquid equilibria for micelle, colloid and microemulsion systems. The Carnahan-Starling equation was used for the hard sphere repulsion. The Yukawa potential was used to describe both the attractive dispersion and the double-layer repulsion. By using the established EOS, the osmotic pressures for charged colloid, uncharged micelle, uncharged and weakly charged microemuslion, the phase equilibria for uncharged micelle and charged colloid systems were studied.

Preparation and Characterization of the System SiO_2-CaO-P_2O_5 Bioactive Glasses by Microemulsion Approach

The system of SiO2-CaO-P2O5 bioactive glasses （BG） were successfully synthesized by microemulsion approach. X-ray diffraction （XRD）,scanning electron micro scopy（SEM） and energy dispersive X-ray （EDX） analyses, transmission electron microscopy（TEM）,Fourier transform infrared spectroscopy （FTIR）, BET N2 gas adsorption analysis techniques were utilized in order to evaluate the phase composition, dimension, morphology, interconnectivity of pores and particle size of the synthesized BG respectiveely. The biocompatibility of BG was assessed by using dimethylthiazol diphenyl tetrazolium bromide （MTT）.The BG scaffolds were implanted in rabbit mandibles and studied histologically.The results showed that the BG with a particle size less than 100 nm was prepared successfully. The measured BET specific surface area and pore volume was 113.9 m2/g and 0.28 cm3/g respectively. Cell cultures revealed that BG has been shown to have good biocompatibility and is also beneficial to the survival of Schwann cells, which can promote cell proliferation in vivo assay indicating that the BG can promote osteoconductivity.

Study on the Phase Behavior of Supercritical CO2/Dynol-604/Water System and Solubilization of Methyl Orange in the Microemulsions

It was found that Dynol-604, a non-fluorous and no silicon-containing nonionic surfactant, was soluble in supercritical (SC) CO2. The phase behavior of SC CO2/Dynol-604/water system was studied. The results showed that one-phase water-in-CO2 microemulsions could be formed. The solubilization of methyl orange in the microemulsions proved further the existence of water domain in the microemulsions.

Experimental study on the dispersion behavior of a microemulsion collector and its mechanism for enhancing low-rank coal flotation

As the poor dispersion of oily collectors and the inferior hydrophobicity of the mineral surface, the lowrank coal has an unsatisfactory flotation performance when using traditional collectors. In this paper, an ionic liquid microemulsion was used as a collector to enhance its floatability. Flotation test results demonstrated the microemulsion collector exhibited a superior collecting ability. A satisfactory separation performance of 78.66% combustible material recovery was obtained with the microemulsion collector consumption of 6 kg/t, which was equivalent to the flotation performance of diesel at a dosage of25 kg/t. The dispersion behavior of the microemulsion collector was investigated using the CryogenicTransmission Electron Microscopy. The interaction mechanism of the microemulsion collector on enhancing the low-rank coal flotation was elucidated through the Zeta potential and contact angle measurements, the Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis.The microemulsion collector exhibited superior dispersibility, which was dispersed into positively charged oil droplets with an average size of 160.21 nm in the pulp. Furthermore, the nano-oil droplets could be more efficiently adsorbed on the low-rank coal surface through electrostatic attraction, resulting in the improvement of its hydrophobicity. Thus, the microemulsion collector shows great application potential in improving the flotation performance of low-rank coal.

Performance evaluation of microemulsion acid for integrated acid fracturing in Middle Eastern carbonate reservoirs

Considering the characteristics of carbonate reservoirs in the Middle East,a low-viscosity microemulsion acid that can be prepared on site and has an appropriate retardation ability was developed.It was compared with four conventional acid systems(hydrochloric acid,gelled acid,emulsified acid and surfactant acid)through experiments of rotating disk,multistage acid fracturing and core flooding with CT scanning.The micro-etching characteristics and conductivity of fracture surfaces were clarified,and the variation of saturation field during water invasion and flowback of spent acid and the recovery of oil phase relative permeability were quantitatively evaluated.The study shows that the addition of negatively charged agent to the oil core of microemulsion acid can enhance its adsorption capacity on the limestone surface and significantly reduce the H+mass transfer rate.Moreover,the negatively charged oil core is immiscible with the Ca^(2+)salt,so that the microemulsion acid can keep an overall structure not be damaged by Ca^(2+)salt generated during reaction,with adjustable adsorption capacity and stable microemulsion structure.With high vertical permeability along the fracture walls,the microemulsion acid can penetrate into deep fracture wall to form network etching,which helps greatly improve the permeability of reservoirs around the fractures and keep a high conductivity under a high closure pressure.The spent microemulsion acid is miscible with crude oil to form microemulsion.The microemulsion,oil and water are in a nearly miscible state,with basically no water block and low flowback resistance,the flowback of spent acid and the relative permeability of oil are recovered to a high degree.

Synthesis of Micro-Mesoporous Ti-MOR/Silica Composite Spheres in Oil-in-Water Microemulsion System

The hierarchically structured micro-mesoporous spheres(MMS) composed of mesoporous silica and Ti-containing mordenite (Ti-MOR) zeolite were self-assembled in an oil-in-water microemulsion system containing tetrabutyl orthosilicate as silica source, cetyltrimethylammonium bromide as template and aluminum sulfate as additive. The composite materials possessed the connatural microporosity of zeolite together with the disordered mesopores(5.41 nm) in silica part. With a special focus on the importance of aluminum sulfate additive, a possible formation mechanism has been proposed, in which double electrostatic interactions played the crucial role of mediating the mesosilica species and zeolite crystals. The obtained MMS materials, with a tunable particle dimension(250-720 μm) and a changeable content of active component Ti-MOR(44%-70%), showed enhanced catalytic activity and lifetime in the liquid-phase ammoximation of cyclohexanone in comparison to the parent Ti-MOR powder.

Rheological characteristics of drug-loaded microemulsions and their printability in three dimensional printing systems

Rheological properties of microemulsions(MEs) and their printability in three dimensional printing(3DP) systems were investigated.A series of MEs with different contents of oil phase were prepared using sonication method with ibuprofen as model drug and soybean lecithin as emulfier.Stationary and transient rheological properties of MEs were investigated by ARES-SRF using concentric cylinders measuring systems.3DP systems with piezoelectric drop-on-demand print heads were employed to test the printability of the MEs.Results demonstrate that the apparent viscosity and dynamic linear viscoelastic regions of the MEs are the most important parameters for continuous and stable printing of MEs by 3DP.The incorporation of drug in the MEs has little influence on the MEs' stationary rheological behaviors and dynamic viscoelasticity,but the concentration of oil phase has a strong influence on them.The rheological property of binder liquids has a close relationship with their printability in 3DP system.