Micro emulsions

An emulsion drying method allows for the synthesis of particles in a more spherical shape, even at 300 °C [61]. However, the crystallinity is low and well-crystallized C-LiFeP04 powders were obtained only after calcinations at 750 °C. In addition, the particles are big (only sub-micron sized), unless buming-out the emulsion-dried precipitates under such conditions that lead to a very high carhon concentration coming from the burning of the oil. 

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For a number of years HF-A oiTin-water emulsions have been used as a fire-resistant hydraulic medium for pit props. Concern over maintenance costs and operational life has created interest in a better anti-wear type fluid. Micro-emulsions are known to give better wear protection... 

Michler s kelene, as photoredox initiator 102 micro-emulsion poly rnerization 64, 250 distinction from emulsion and ininiemulsion... 

Recently, Mark and co-workers also reported on organophilic silica formed by the combination of the sol-gel procedure and water-in-oil micro-emulsion method, in which methacryloyloxypropyltrimethoxysilane was used as one component of silica matrix [8]. The size of the silica particle was controlled by the content of water and emulsifier used. The surface of the particles was effectively covered with methacryloyl. organic groups. This organophilic silica is expected to be used as a novel component of composite materials. 

Micro emulsions based on a heparin-chitosan complex suitable for oral administration based on ingredients acceptable to humans were studied with or without biologically active ingredients. Appropriate mixing and modifications of these microemulsions lead to nanometer-sized heparin-chitosan complexes [108]. 

Hager M, Currie F, Holmberg K (2003) Organic Reactions in Micro emulsions. 227 53 - 74 Hausler H, Stiitz AE (2001) D-Xylose (n-Glucose) Isomerase and Related Enzymes in Carbohydrate Synth esis.215 77-114... 

Another important interaction that needs to be considered is the hydrophobic interaction. This can be most easily thought of in terms of two immiscible liquids such as oil and water being induced to mix by adding surfactants, to form (micro) emulsions. The exact structure of the phase formed depends heavily on the relative compositions of the various phases and the structure of the surfactant (see Figure 6.4). 

PtRu nanoparticles can be prepared by w/o reverse micro-emulsions of water/Triton X-lOO/propanol-2/cyclo-hexane [105]. The bimetallic nanoparticles were characterized by XPS and other techniques. The XPS analysis revealed the presence of Pt and Ru metal as well as some oxide of ruthenium. Hills et al. [169] studied preparation of Pt/Ru bimetallic nanoparticles via a seeded reductive condensation of one metal precursor onto pre-supported nanoparticles of a second metal. XPS and other analytical data indicated that the preparation method provided fully alloyed bimetallic nanoparticles instead of core/shell structure. AgAu and AuCu bimetallic nanoparticles of various compositions with diameters ca. 3 nm, prepared in chloroform, exhibited characteristic XPS spectra of alloy structures [84]. 

Micro-emulsion formulations of cationic softeners are available and are claimed to have superior fibre penetration properties [484]. Figure 10.59 shows the sorption of a micro-... 

Figure 10.59 Sorption kinetics of micro-emulsion cationic softener formulation at different temperatures on cotton fabric [484], Initial concentration 3 g/kg fibre, liquor ratio 15 1...

C Solans and H Kuneida, Industrial applications of micro emulsions (New York Marcel Dekker, 1996). 

M Bourrel and R S Schechter, Micro-emulsions and related systems (New York Marcel Dekker, 1988). 

Parvinzadeh, M. and Hajiraissi, R. (2008) Effect of nano and micro emulsion silicone softeners on properties of polyester fibers. Tenside Surfactants Detergents, 45 (5), 254-257. 

The shake-flask method has some drawbacks, however. One problem that occurs occasionally is the formation of micro-emulsions which remain stable for hours or days, and prevent the two solvent layers from separating. In this case it is not possible to measure the concentration of analyte in each phase. More generally, the upper and lower range of log D values is limited by problems of solution handling. For very high log D values the sample is much more soluble in octanol than in water. For example, if log D is 4 the sample is 10,000 times more soluble in octa-... 

Biotin-BMCC is insoluble in water and must be dissolved in an organic solvent prior to addition to an aqueous reaction mixture. Preparing a concentrated stock solution in DMF or DMSO allows transfer of a small aliquot to a buffer reaction. The upper limit of biotin-BMCC solubility in DMSO is approximately 33 mM or 17 mg/ml. In DMF, it is only soluble to a level of about 7 mM (4 mg/ml). Upon addition of an organic solution of the reagent to an aqueous environment (do not exceed 10 percent organic solvent in the aqueous medium to prevent protein precipitation), biotin-BMCC may form a micro-emulsion. This is normal and during the course of the reaction, the remainder of the compound will be driven into solution as it couples or hydrolyzes. 

Fluorescent silica nanoparticles, called FloDots, were created by Yao et al. (2006) by two synthetic routes. Hydrophilic particles were produced using a reverse micro-emulsion process, wherein detergent micelles formed in a water-in-oil system form discrete nanodroplets in which the silica particles are formed. The addition of water-soluble fluorescent dyes resulted in the entrapment of dye molecules in the silica nanoparticle. In an alternative method, dye molecules were entrapped in silica using the Stober process, which typically results in hydrophobic particles. Either process resulted in luminescent particles that then can be surface modified with... 

Unsaturated polyesters with neutralized terminal carboxyl acid groups (EUP) are efficient emulsifiers which, at a sufficient concentration, may form aqueous microemulsions. Micro emulsions are liquid dispersions of translucent (opalescent or transparent) appearance. Their disperse phase contains particles of diameters between 20 and 80 nm which closely approaches the diameters (5-15 nm) of micelles [114]. 

Prince LM (1977) Micro emulsions - theory and practice.Academic Press, Inc... 

C02-philic molecules have been utilized for the design of metal-mobilizing ligands to be used in SCCO2 [67-69,135-137], e.g., as shown in Fig. 7a [55] and for the synthesis of surfactants that form micelles, emulsions, and micro emulsions in CO2, e.g., as shown in Fig. 7b. [70] Polymer solubility in SCCO2 has been studied [71] and utilized for polymer synthesis [72-74]. Recently, DeSimone and co-workers synthesized high-molar-mass fluoropolymers in SCCO2, and studied the polymerization kinetics [75]. 

Carbosilane dendrimers with perfluorinated end groups in perfluorohexane were studied by Stark et al. [308]. The significant deviations from simple diffusion that are observed in the NSE data in this case are attributed to shape fluctuations following a procedure that had been developed for the analysis of micro-emulsion droplet fluctuations [309]. 

Fig. 6.20 Small angle scattering intensity (triangles log I) and effective diffusion DgfKQ) obtained from g=A carbosiloxane dendrimers with perfluorinated end groups in perfluo-rohexane. The dashed line is a fit to the prediction of a model for shape fluctuations of micro-emulsion droplets, the resulting bending modulus was 0.5 k T. (Reprinted with permission from [308]. Copyright 2003 Springer Berlin Heidelberg New York)...

Systems and materials. The reaction was carried out at several compositions in an ionic and in a nonionic system. The ionic system consisted of an emulsifier (49.6 wt % cetyltrimethyl ammonium bromide (CTAB)/50.4% n-butanol), hexadecane, and water. The nonionic emulsifier consisted of 65.7% polyoxyethylene (10) oleyl ether (Brij 96) and 34.4% n-butanol, again with hexadecane and water. In both systems, mlcroemulslon (pE) compositions used were obtained by diluting an initial 90 weight percent (%) emulsifler/10% oil mixture with varying amounts of water. Micro-emulsion samples thus obtained had final compositions of 30 to 80% water. Phase maps describing these systems have been published (10-11). 

Absorbance measurements, pyridinium ion with CN- in micro-emulsions, 177 Absorption insulin... 

Sonogen/liquid C5F12 micro emulsion in C5F12 Clinical trials [39]... 

Recently, the synthesis of nano-sized HA has been proposed via reverse-micro-emulsion preparation, which is reported to be effective for controlling the hydrolysis and polycondensation of the alkoxides of the constituents. Using this preparation route, the nanoparticles crystallize directly to the desired phase at the relatively low temperature of 1050 °C and maintain surface areas higher than 100 m g after calcination at 1300 °C for 2h [107-109]. 

Finally, control of fluorapatite particle size (from 15 nm to 200 pm) and morphology can be achieved by varying precipitation conditions using aqueous precipitation from a micro-emulsion or by biomimetic synthesis in a gelatin matrix [129],... 

They are emulsions with droplet diameters in the range 0.01 to 0.1 pm. It is formed when the oil-water interfacial tension approaches zero. Micro emulsions represents an intermediate state between micelles and ordinary emulsions. They are usually of low viscosity. 

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