The hydrophobic gold nanomaterials with various morphologies and sizes were prepared by ethanol reduction under the routine heating in cetyltrimethylammonium bromide(CTAB) or octadecylamine(C18NH2)/n-heptane/ ethanol/ HAuCl4(4H2O W/O microemulsion system.

The W/O microemulsion of Tween 80-Span 80/ethanol/butyl butyrate/H_2O to envelop insulin(INS) was prepared.

The hydrophobic silver nanoparticles protected with octadecylamine were fabricated by using formamide as reducing agent in the octadecylamine/n-butanol/n-heptane/formamide/AgNO_3(aq) W/O microemulsion under the state of refluxing.

At first, Pd(NO3)2 was recycled from the waste Pd-C catalyst, then, the palladium nanoparticles with size of 5 nm to 200 nm were generated in the O/W microemulsion of sodium dodecyl sulfate (SDS), Brij30 and H2O system by using nonionic surfactant Brij30 as the reducing agent.

Fine particles of polyaniline were prepared in (An+O/W microemulsion)two phase system in which the An phase was used as a monomer source and the O/W microemulsion phase for polymerization.

In this paper, a review is presented focusing on the application of reversed micelles or w/o microemulsions to synthesizing nano-sized ultrafine particles, including precip itation in reversed micelles, preparation of colloidal catalysts, preparation of semi-conductors, magnetic particles and ceramic powders, etc.