Formation in microemulsions

For Cu(ll) in water adsorbed on silica gels it was reported 5 that in gels with small pores isolated hydrated ions are detected at 77 K5 in pores larger than -4 nm a broad signal is superimposed on the spectrum of isolated ions. The appearance of the broad signal indicates aggregation of cations and the presence of bulk or freezable water. In a recent publication the Cu(ll) probe was used to test the possibility of ice formation in microemulsions, jce formation was detected in one of the microemulsions studied for very slow cooling rates from -300 K to 77 K. 

Systematic investigations into the kinetic aspects of silica formation in microemulsions have been undertaken by only a few researchers (23,24,29). Various forms of useful qualitative and semi-quantitative kinetic information are available, however. For example, size exclusion chromatography (SEC) was used by Espiard et al. (22) to monitor TEOS concentration as a function of time for different R values (R = 4, 6, 10). An initial period of rapid reaction (approximately first 6 h) was observed,... 

Unilamellar vesicles have been used as a reactor for the synthesis of nanos-meter-scale magnetic particles (13,14). By adding alkaline solution to vesicles containing intravesicular solutions of Fe2+ and Fe3+, the Fe /Fe resulted in the formation of membrane-bound discrete particles of different ion oxide particles. These results together with the particle formation in microemulsion are not only of interest in colloid chemistry but also have significance in mineralization in biosystems, such as magnetotactic bacteria, where particles are formed within enclosed organic compartments. 

Therefore the conclusions that we can draw at this stage from these experimental results on particle formation are very general and certainly need further investigation. To summarize, I can state that the mechanism of particle formation in microemulsions is certainly different from that in homogeneous media. (This difference is induced by the structures present in the microemulsion.) Taking into account the solubility properties of microemulsions, we can think of carrying out a reaction in little individual nanoscale... 

Nanoparticle Formation in Microemulsions Mechanism and Monte Carlo Simulations... 

Tojo, C., Blanco, M.C., and L6pez-Quintela, M.A. 1998. The influence of reactant excess and film fiexibility on the mechanism of nanoparticle formation in microemulsions A Monte Carlo simulation. Langmuir, 14, 6835-6839. 

Tojo, C., Barroso, F., and de Dios, M. 2006. Critical nucleus size effects on nanoparticle formation in microemulsions A comparison study between experimental and simulation results. Journal of Colloid and Interface Science, 296, 591-598. 

Piazza, GJ. Lipoxygenase catalyzed hydroperoxide formation in microemulsions containing nonionic surfactant. Biotech Lett 1992 14 1153-58. 

Gratzel, C. K., Kira, A., Jirousek, M., and Gratzel, M., Dimer cation formation in microemulsions media duroquinone-sensitized photooxidation of 2,6-dimethylnaphthalene and tetrathioful-valene, /. Phys. Chem., 87, 3983, 1983. 

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