• Journal of the Korean Ceramic Society
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• v.41 no.3
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• pp.242-246
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• 2004

Nano-sized a-alumina with a narrow distribution was prepared by using Flame Spray Pyrolysis (FSP). The microemulsion of water in oil (W/O) was prepared to make ultrafine droplets for FSP process. Kerosene (fuel) as a continuos phase and Al(NO$_3$)$_3$$.$9$H_2O$ (oxidizer) aqueous solution as a dispersed phase were prepared for microemulsification. The microemulsion with dispersion stability was obtained by adjusting the composition of 80 vol% kerosene, 10 vol% aqueous solution, and 10 vol% emulsifying agent. Microemulsion was sprayed onto the flame by using two-fluid nozzle spray gun under the condition of 0.03 ㎫ air pressure. The synthesized products were $\alpha$-alumina phase with the size of 20 to 30 nm.

• Membrane and Water Treatment
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• v.12 no.2
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• pp.75-82
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• 2021

This study aimed to prepare a W/O nonionic microemulsion system(MEs) consisting of OP-4[polyoxyethylene(4) nonylphenol], OP-7[polyoxyethylene(7) nonylphenol], 1-hexanol, D2EHPA, kerosene and HCl solution and applied to the extraction of La(III) from chloride aqueous solution within the polysulfone hollow fiber contactor (HFC),laboratory-scale experiments were carried out to investigate the recovery of La(III) using as-prepared microemulsion from the simulation wastewater containing La(III),Al(III) and Fe(III). The right weight ratio(Rs) of OP-4 to OP-7 was firstly confirmed through determination of the solubilization capacity of HCl solution(W0,HCl) in microemulsion, the effect of several factors such as the HCl concentration, temperature and effective extraction time on the extraction efficiency of La(III) was discussed. Results showed that the acceptable Rs was 4:6 to prepare the W/O MEs. The extraction yield of La(III) increased with the increasing of HCl concentration, temperature and effective extraction time and reaches to 97.3% while using five-stage modules. The recovery yield of La(III) from simulation La-bearing wastewater was 90.6%.

• Journal of the Korean Applied Science and Technology
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• v.19 no.1
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• pp.56-62
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• 2002

Microemulsion is stable to aggregation, sedimentation, fusion and has $3nm{\sim}200nm$ of particle size which is transparent and semitransparent. The isoflavone as a derivatives of Flavone is colorless crystalline compounds. It has similar basic structure to steroid materials which is hormone that acts to skin physiological phenomenon. On this study, we tried to search and demonstrate system content rate of dermal translocation system for cosmetics using O/W type microemulsion containing isoflavone. We manufactured O/W microemulsions by phase inversion emulsification method. It's was found that POE(20) monostearate with HLB value 14 caused microemulsion to be formed, which had $4nm{\sim}18nm$ of average diameter and $3nm{\sim}33nm$ of particle size distribution. Apparent viscosities of the microemulsions have increased in proportion to add surfactant dose.

• Applied Chemistry for Engineering
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• v.22 no.4
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• pp.416-422
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• 2011

In this study, the effect of cosurfactant on the phase equilibrium and dynamic behavior was studied in systems containing NP7 nonionic surfactant solutions and nonpolar hydrocarbon oils. All cosurfactants used during this study such as n-pentanol, n-octanol and n-decanol acted as a hydrophobic additive and thus promoted the transition from an oil in water (O/W) microemulsion (${\mu}E$) in equilibrium with an excess oil phase to a three-phase region containing excess water, excess oil, and a middle-phase microemulsion and further to a water in oil (W/O) ${\mu}E$ in equilibrium with the excess water phase. The transition temperature was found to decrease with both increases in the chain length and amount of addition of a cosurfactant. Dynamic behavior studies under O/W ${\mu}E$ conditions showed that an oil drop size decreased with time due to the solubilization into micelles. On the other hand, both the spontaneous emulsification of water into the oil phase and the expansion of oil drop were observed under W/O ${\mu}E$ conditions because of the diffusion of surfactant and water into the oil phase. Under conditions of a three-phase region including a middle-phase ${\mu}E$, both the rapid solubilization and emulsification of the oil into aqueous solutions were found mainly due to the existence of ultra-low interfacial tension. Dynamic interfacial tension measurements have been found to be in a good agreement with dynamic behavior results.

• Korean Chemical Engineering Research
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• v.46 no.2
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• pp.356-368
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• 2008

The effects of cosurfactant on silica nanoparticles were investigated in systems containing surfactant, oil and aqueous ammonia solution where nanoparticles were prepared using a single phase water-in-oil (W/O) microemulsion. For the same oil phase, a single phase region was dependent on the interaction between surfactant and oil. For the cyclohexane system, NP-5 surfactant showed a wider single phase region than NP-4. The addition of n-propanol as a cosurfactant resulted in an increase or a decrease of a single phase W/O microemulsion region depending on the continuous oil phase. For both cyclohexane and isooctane systems, the addition of n-propanol resulted in a decrease in the single phase region. On the other hand, for n-heptane system, the addition of n-propanol expanded a single phase W/O microemulsion region. Silica nanoparticles prepared within a single phase region showed that relatively large number of particles of irregular shape were obtained with the addition of n-propanol to NP surfactant system. The addition of n-propanol to LA-5 surfactant and n-heptane system produced a decrease in average particle size and an increase in the number of particles formed due to a decrease in the intermicellar exchange rate among microemulsion droplets.

• Korean Chemical Engineering Research
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• v.40 no.6
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• pp.769-777
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• 2002

Using four components - nonionic surfactants, water, hydrocarbon oil and an alcohol as cosurfactant, 12 types of cleaning agents were prepared, and their physical properties such as surface tension, viscosity, electroconductivity and phase stability were measured. As the formulated cleaning agents have low surface tensions(30.5-31.1 dyne/cm) and low viscosities (1.6-7.2 c.p.), they are satisfied with the general physical properties of water-in-oil(W/O) microemulsions for their industrial use. They showed a tendency that their temperature range for stable one-phase microemulsion decreased in accordance with the increase of alcohol/surfactant(A/S) ratio in the formulations. However, the temperature range of one-phase microemulsion was much more affected by hydrophilic lipophillic balance(HLB) value of the nonionic surfactant which increased its temperature range and it increased in accordance with the higher HLB value in the formulations. And the maximum content of water which can keep stable one-phase W/O microemulsion was measured at each sample. In addition, their temperature range for stable one-phase microemulsion was also measured. It was confirmed that the selection of surfactant type was very important for formulating a cleaning agent, since the W/O microemulsion system with the nonionic surfactant of the lower HLB value showed better cleaning efficacy that of the higher HLB value for abietic acid as a soil, which was used for preparing a rosin-type flux. In the formulated cleaning agents with the increase of A/S ratio in the formulations, however, there was no significant difference in cleaning efficacy. It was investigated that the differences of their cleaning efficacy was affected by the change of the condition of temperature and sonicating frequency as important factors in the industrial cleaning. That is, the higher, their cleaning temperature and the lower, their sonicating frequency, the more increased, their cleaning efficacy. Furthermore, using optical instruments like UV/Visable Spectrophotometer and FT-IR Spectrometer, their cleaning efficacy for abietic acid was measured. The removal of soil from the contaminated rinse water was measured by gravity separation method in the rinse bath. As a result, the cleaning agent system having the nonionic surfactant of HLB value 6.4 showed over 85% water-oil separation efficacy at over $25^{\circ}C$. Therefore, it was demonstrated in this work that the formulating cleaning agents were very effective for cleaning and economical in the possible introduction of water recycling system.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.21 no.2
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• pp.22-48
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• 1995

This study was investigated to search for the effects of the structure of each component in four-component O/W microemulsion system on its formation region, droplet size and stablilty. The results was that the more number of OH site, the shorter carbon chain length of polyol, the larger formation region of microemulsion was showed. The small microemulsion droplet was obtained on condition that the polatry of oil was large and carbon chain length of hydrophobic group of surfactant was long. In using satrated hydrocarbon (such as liquid paraffin, squalane) as dispersed phase, the stability of microemulsion was better than aromatic oil phase.

• Journal of the Korean Chemical Society
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• v.52 no.2
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• pp.164-168
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• 2008

CaWO4 crystals were synthesized by a microemulsion method. Various sizes and shapes of CaWO4 were obtained by changing the molar ratio (w) of H2O to CTAB. At w=5 and 10, oval CaWO4 crystals with length of 100 nm and 500 nm were obtained, respectively. At w=20, rod-like CaWO4 crystal with length of 1 μm was obtained. The sphere CaWO4 crystal with length of about 2~3 μm was obtained at w=30. The CaWO4 crystal morphology changes from oval to sphere via a rod by aggregation with increasing the molar ratio of H2O to CTAB.

• YAKHAK HOEJI
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• v.45 no.6
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• pp.634-640
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• 2001

Ibuprofen is one of the nonsteroidal anti-inflammatory drugs (NSAID) and has shown antiinflammatory; antipyretic, and analgesic activity in both animals and humans. But it causes gastric mucosal abnormalities including edema, erythema, and submucosal petechial hemorrhages and erosin in human. In addition, based on the pharmaceutical point of view the compression and dissolution ability of ibuprofen is known as poor. Therefore we studied to develop novel formulation containing water-insoluble drug, ibuprofen, using microemulsion consisting of surfactant, oil phase, and water phase was prepared for the purpose of increasing its bioavilability The physicochemical properties such as particle size, dissolution rate, solubility of ibuprofen in the system were determined. After oral administration of ibuprofen containing the microemulsion system, to Sprague-Dawley rats, pharmacokinetic parameters were also obtained. For the formulation in the study, oleic acid, linoleic acid, and several kinds of glycerides and triglycerides were used as an oil phase with several surfactants. Diethylene glycol monoethyl ether (Transcuto $l^{ }$) or saturated polyglycolized glycerides (Labrafil $^{ }$)as surfactant was used, the domain of microemulsion was wide. The diameter of o/w microemulsion was ranged from 90 to 220 nm. Microemulsion, prepared with unsatulated polyglycolized glycerides (Labrafil $^{ }$) and the 2 : 1 molar mixture of diethylene glycol monoethyl ether (Transcuto $l^{ }$)/polyoxyethylene(4) lauryl ether (Bri $j^{ }$ 30) , is expected to be promising system that increased the bioavilability of ibuprofen.ibuprofen.

• Archives of Pharmacal Research
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• v.27 no.3
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• pp.351-356
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• 2004

A transdermal preparation containing diclofenac diethylammonium (DDA) was developed using an O/W microemulsion system. Of the oils tested, lauryl alcohol was chosen as the oil phase of the microemulsion, as it showed a good solubilizing capacity and excellent skin permeation rate of the drug. Pseudoternary phase diagrams were constructed to obtain the concentration range of oil, surfactant and cosurfactant for microemulsion formation, and the effect of these additives on skin permeation of DDA was evaluated with excised rat skins. The optimum formulation of the microemulsion consisted of 1.16% of DDA, 5% of lauryl alcohol, 60% of water in combination with the 34.54% of Labrasol (surfactant)/ethanol (cosurfactant) (1:2). The efficiency of formulation in the percutaneous absorption of DDA was dependent upon the contents of water and lauryl alcohol as well as Labrasol: ethanol mixing ratio. It was concluded that the percutaneous absorption of DDA from microemulsions was enhanced with increasing the lauryl alcohol and water contents, and with decreasing the Labrasol:ethanol mixing ratio in the formulation.