Papers by Keyword: Microemulsion

Abstract: A new O/W microemulsion system for transdermal matrine delivery was developed in order to improve the skin permeability and solubility of matrine. Various factors were investigated including solubility of matrine,the skin permeability of matrine aiming to choose suitable surfactants, cosurfactants and oils. By drawing the pseudo-ternary phase diagrams, the basic prescription of microemulsion were determined. A simplex lattice experiment design was adopted to optimize the composition of microemulsions.The mathematical software Matlab be used to calculate the predicted values to determine the optimization of microemulsion formulation.

Abstract: Lanthanum hexaaluminates LaAl12O19-δ modified by transition-metal ion (Mn, Co and Ni ) were prepared through co-precipitation of metal nitrates within the water phase of a Triton X-100/n-hexanol/cyclohexane reverse microemulsion. The effects of different modification ion and the precursor solution concentration on the catalytic property of catalysts were investigated. The structure and properties of these samples were characterized by XRD, BET, SEM and TG-DTA. The stabilities of catalysts were assessed by measuring the activities for combustion of methane. Upon calcination at 1200°C, when the precursor solution concentration is 0.75M, the sample LaMnNiAl₁₀O_19-δ retained a specific surface area of 40.34m²/g and showed a excellent activity for methane combustion, which temperature at 10% , 90% and 99% conversion were 420 °C, 690 °C and 760 °C, respectively.

Abstract: Copper oxide nanoparticles have been synthesized using micro reactors made of bis (2-ethylhexyle) sulfosuccinate (AOT)/water/n-Hexane microemulsions. The controls of particles size was achieved by varying water to surfactant molar ratio (W₀). At constant of surfactant concentration the increases in value of W₀ increased the population of micelles and resulted in lager particle size. Their sizes and appearance were characterized by TEM, SEM, Zetasizer, uv-visible methods. Scanning electron microscopy (SEM) showed the spherical morphology of as prepared CuO nanoparticles. The Transmission electron microscopy (TEM) showed 85 nm size of as prepared CuO particles.

Abstract: Lipase from Candida rugosa (CRL) was used to catalyze the transesterification of vinyl acetate with 2-hydroxymethyl-1,4-benzodioxan in ionic liquid microemulsions (H₂O/[BmiPF₆, water in 1-butyl-3-methylimidazolium hexafluorophosphate), and the results demonstrated that CRL could preserve higher catalytic activity in H₂O/[BmiPF₆ microemulsions.

Abstract: Decylglucoside is a non-ionic, non-toxic, biodegradable surfactant. This work aimed to establish composition where stable microemulsions could form using hydrophilic lipophilic deviation (HLD) concept to optimise the formulations. Scanning for suitable ratios of surfactant and co-surfactant was carried out by altering the surfactant/co-surfactant (S/CoS) ratios with two co-surfactants and seven different oils in order to find the optimum formulations. From the optimal S/CoS ratios, pseudo-ternary phase diagrams by dilution were subsequently performed, leading to obtain microemulsion zones. The zones of microemulsions could be observed in the systems composed of decylglucoside/sorbitan monooleate/isopropyl myristate/water at the 0.10/0.90 and 0.20/0.80 S/CoS ratios and decylglucoside/sorbitan monooleate /isopropyl palmitate/water at the 0.10/0.90, 0.15/0.85 and 0.20/0.80 S/CoS ratios. The microemulsion zones of two systems were similar and found at high surfactant concentrations. However, the studied decylglucoside microemulsion systems were interesting in drug and cosmetic applications because it consisted of non-ionic surfactant and co-surfactant, resulting low toxic products.

Abstract: To prepare nanoscale coordination polymers (NCPs) which can exhibit intense luminescence have attract an increasing interest. In this paper, we present the synthesis of a novel example of discus-like luminescent nanoscale Eu (III)-carboxylate coordination polymers. The organic ligand is a derivative of terephthalate (Na₂L) with a big side group. The Eu (III)-L NCPs was synthesized through microemulsion method, and the morphology can alter along with the changing of metal: ligand ratios. XRD results reveal that the self-assembled disk-like NCPs exhibit long-range ordered structures. The luminescent measurements showed that the resultant NCPs not only exhibits typical fluorescence of Eu (III), but also can maintain the inherent fluorescence of the ligands.

Abstract: Fundamentally, ceria particle had ability to store, transport and release oxygen, which was identified as oxygen storage capacity (OSC). Due to this OSC ability, ceria became the most important component in the three-way catalyst. With the addition of zirconia into the ceria resulting in better performance in three-way catalyst as it increased or improved thermal stability and also promotes the redox properties. This study was conducted to investigate the effects of heat treatment on the structure and physical property of nanocrystalline Ce-Zr-O solid solution. Microemulsion method was used for preparation of Ce-Zr-O solid solution, and heat treatment investigation was applied towards the synthesized nanocrystalline Ce-Zr-O solid solution. The phase and crystal structure of Ce-Zr-O solid solution were determined using XRD analysis. While, the modification of surface area and porosity size over the wide range of calcination temperatures range from 300°C to 700°C was investigated using BET Analyzer. XRD analysis confirmed the Ce_0.75Zr_0.25O₂ solid solution was succesfully synthesized in the research. The results exhibited the effect of heat treatment on the decreasing of surface areas and porosity profiles of the Ce_0.75Zr_0.25O₂. Despite of the reduction of surface areas at elevated temperatures, the study found the promising results that the enhancement of thermal stability of ceria by addition of zirconia.

Abstract: A novelsynthetic method is developed to prepare nano-sized FePO₄ powdersused as cathode materials of lithium ion batteries. The samples are preparedvia a microemulsion system in a H₂O/cyclohexane/Triton x-100/n-butylalcohol, and then sinter at different temperatures (380°C，460°C，550°C，650°C)for 3h. The thermal stability，structure，morphology and particle size are investigated by means of TG/DSC, X-raydiffraction (XRD), field emission-scanning electron microscopy (FE-SEM), andthe electrochemical properties are characterized by cyclic voltammetry (CV) andgalvanostatic charge and discharge tests. Results show the grain size of FePO₄particles sintered at 460°C and 380°C for 3h ranges from 10nm to 20nm, and thecrystal structure is amorphous. The initial discharge specific capacity of FePO₄cathode sintered at 460°C for 3h reaches 139mAhg^-1 and 110mAh/g,respectively, at 0.1C and 0.3C. Increasing sintering temperature leads to thesmall particles agglomeration and the crystalline growth, and the crystalstructure changes from amorphous to trigonal when the sintering temperature isup to 550°C. The discharge specific capacity also decreases with the increase ofthe sintering temperature. These results suggest that nano-sized particles andamorphous structure can significantly improve the performances of FePO₄cathode.

Abstract: Several rare earth phosphate nanomaterials have been synthesized. It is shown that during the Micro emulsion preparation process, the size and morphology of rare earth phosphate nanomaterials could be tuned by changing the conditions of the micro emulsion system, which have a significant effect on the fluorescence properties.

Abstract: The aim of the study was to synthesis the CdS nanoparticles via AOT-water-n-heptane microemulsion technique. Ternary phase diagram was constructed to obtain the concentration range of oil, surfactant and water. Three main phases form on the ternary phase diagram of AOT-water-n-heptane, which were gel, cloudy and clear phases. The clear phase was heptane rich region. Meanwhile, cloudy phase have consisted two phases and the gel phase was due to high concentration of AOT. The result showed that clear phase region shrink when the Cd²⁺ and S^2-solvent was added or replaced the water component of the tertiary system.The existence of CdS nanoparticles with average size of 14.0 nm has been calculated by using UV-Vis Spectrometry meanwhile the TEM image showed that the size of CdS nanoparticles was about 49-89 nm. It also have concluded that the same concentration at solvents Cd²⁺ and S^2- does not effected the size of nanoparticles.