Microemulsions dilution

Trotta, M. Gallarate, M. Carlotti, M.E. Morel, S. Preparation of griseofulvin nanoparticles from water-dilutable microemulsions. Int. J. Pharm. 2003, 254 (2), 235-242. 

Similarly, LLCs can aid in the control of nanoparticle synthesis. The majority of this literature involves dilute, microemulsion surfactant conditions (see review, [52]). However, there are still numerous examples of these particles synthesized in the condensed phases of LLCs. When LLCs are employed, analogous to the formation of metal nanowires and lattices, the inorganic precursors (e.g., M + ions) are reduced and solidified. The LLC network provides nano-confinement and nano-control over the diffusion of ions. There are two... 

Shevachman M, Garti N, Shani A, and Sintov AC. (2008). Enhanced percutaneous permeability of diclofenac using a new U-type dilutable microemulsion. Drug Development and Industrial Pharmacy, 34, 403-412. 

A. Spernath, A. Aserin, N. Garti, Fully dilutable microemulsions embedded with phospholipids and stabilized by short-chain organic acids and polyols. J. Colloid Interf. Sci. 299, 900-909 (2006)... 

In comparison with dilution, microemulsion, and pyrolysis, transesterification has attracted more attention. The reason probably is the fact that pyrolysis and microemulsion are costly methods with low-quality biodiesel production compared to the transesterification method (Taher, Al-Zuhair, Al-Marzouqi, Haik, Farid, 2011), and the quality of biodiesel produced in the transesterification is better (mainly due to its lower viscosity) (Ferella et al., 2010). 

However, in the case of mini- and microemulsions, processing methods reduce the size of the monomer droplets close to the size of the micelle, leading to significant particle nucleation in the monomer droplets (17). Intense agitation, cosurfactant, and dilution are used to reduce monomer droplet size. Additives like cetyl alcohol are used to retard the diffusion of monomer from the droplets to the micelles, in order to further promote monomer droplet nucleation (18). The benefits of miniemulsions include faster reaction rates (19), improved shear stabiHty, and the control of particle size distributions to produce high soHds latices (20). 

In a detersive system containing a dilute surfactant solution and a substrate bearing a soHd polar sod, the first effect is adsorption of surfactant at the sod—bath interface. This adsorption is equivalent to the formation of a thin layer of relatively concentrated surfactant solution at the interface, which is continuously renewable and can penetrate the sod phase. Osmotic flow of water and the extmsion of myelin forms foHows the penetration, with ultimate formation of an equdibrium phase. This equdibrium phase may be microemulsion rather than Hquid crystalline, but in any event it is fluid and flushable... 

In sodium bis(2-ethylhexyl) phosphate microemulsions, which are composed of cylindrical micelles in the dilute region, it has been observed that the formation of micellar clusters is characterized by a branched structure as the volume fraction (<1>) of the aggregates increases. At d> > 0.2, these clusters mutually overlap, forming a network expanded overall [283]. 

Different methods are used in microemulsion formation a low-energy emulsification method by dilution of an oil surfactant mixture with water and dilution of a water-surfactant mixture with oil and mixing all the components together in the final composition. These methods involve the spontaneous formation of microemulsions and the order of ingredient addition may determine the formation of the microemulsion. Such applications have been performed with lutein and lutein esters. ... 

Chhatre et al. (1993) have reported that highly selective ort/io-nitration of phenol with dilute nitric acid can be realized by using a microemulsion medium. It seems that in the microemulsion medium, phenol orients in such a way that the phenyl group remains extended towards the side of the organic phase, whereas the hydroxyl group protrudes in the aqueous... 

An additional point is that relatively high concentrations of surfactant, oil and cosurfactant are often used in microemulsions. Thus the volume of the microemulsion pseudophase is large and droplet-bound reactants are therefore diluted. Generally speaking, rate enhancements increase in the sequence microemulsions < micelles < vesicles simply because of a decrease in the volume of the micellar or droplet pseudophase. 

This transition may j-.e. reducing the specific surface energy, f. The reduction of f to sufficiently small values was accounted for by Ruckenstein (15) in terms of the so called dilution effect". Accumulation of surfactant and cosurfactant at the interface not only causes significant reduction in the interfacial tension, but also results in reduction of the chemical potential of surfactant and cosurfactant in bulk solution. The latter reduction may exceed the positive free energy caused by the total interfacial tension and hence the overall Ag of the system may become negative. Further analysis by Ruckenstein and Krishnan (16) have showed that micelle formation encountered with water soluble surfactants reduces the dilution effect as a result of the association of the the surfactants molecules. However, if a cosurfactant is added, it can reduce the interfacial tension by further adsorption and introduces a dilution effect. The treatment of Ruckenstein and Krishnan (16) also highlighted the role of interfacial tension in the formation of microemulsions. When the contribution of surfactant and cosurfactant adsorption is taken into account, the entropy of the drops becomes negligible and the interfacial tension does not need to attain ultralow values before stable microemulsions form. 

Lipid particles can also be prepared by dispersing a hot microemulsion in cold water (2 to 3°C) under stirring. Drawbacks of this process are the frequent need for organic solvents and the relative low particle concentration as a result of the dilution with water [14]. 

Heat capacity measurements should be very useful in determining the local structure in microemulsions. A complete study will involve keeping one component near infigite dilution and vary the ratio of the other two. The standard Cp of the first component will then inform us on the environment of the molecule. This should be done for BE, DEC and H2O as the reference component. 

Liquid detergent formulation A light-duty microemulsion liquid detergent composition, useful for removing greasy soils from surfaces with both concentrated and diluted forms, has been reported. It consists of the following components ... 

The cleaning composition may be used in concentrated or diluted form for cleaning soil from glass and metal parts, among others. This microemulsion shows that, by combining water and oil, metal surfaces can be cleaned effectively. This becomes possible because both oil- and water-soluble dirt is removed by the microemulsion. 

In order to improve the luminescence behaviors and obtain better quantum yields, Zhang et al. [245] have suggested a reflux treatment by diluting w/o microemulsions of CdS nanoparticles with the same w/o microemulsions but substituting the reactant solution with H2O. The water in the w/o microemulsion droplets was removed by the co-surfactant (n-hexanol), the trap sites on the nanoparticle surface decreased improving the crystalHnity and thus the fluorescence efficiency. 

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