Basics of microemulsions

Micro emulsions are either dispersions ofwater in oil or oil in water stabilised by interfacially adsorbed amphiphiles. Normally, a combination of surfactant and co-surfactant is required for stable nanodispersions of fluids, while surfactants like Na-2-bis-sulfosuccinate (Aerosol Orange T or AOT) are able to efficiently stabilise the dispersion without a co-surfactant. Right kind of choice of amphiphiles and their combinations can bring down the oil/water interfacial tension to a very low value to make the dispersions thermodynamically stable. Micro emulsions are thus considered as thermodynamically stable, isotropic andlow viscous nanodispersions of water-in-oil (w/o) or oil-in-water (o/w). 

In the synthesis of nanomaterials, w/o-type nanoreactors are used where the chemical reactions occur in the water pool whose physicochemical characteristics vary region-wise 

Microemulsions Background, New Concepts, Applications, Perspectives. Edited by Cosima Stubenrauch 2009 Blackwell Publishing Ltd. ISBN 978-1 05-16782-6 

Surfactant tail Surfactant head Normal or bulk 

a simple relation (Eq. (6.2)) was proposed by Marciano et al. [3] for AOT-derived micro emulsion systems, namely 

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Forster, T., Guckenbiehl, B., Hensen, H. and von Rybinski, W. (1996) Physico-chemical basics of microemulsions with alkyl polyglucosides. Prog. Colloid Polym. Sci., 101, 105. 

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