Syntheses of copper nanoparticles in gelified microemulsion and in reverse micelles.

Syntheses of nanosized copper crystallites have been carried out in reverse micelles and in gelified microemulsion. The self assemblies have been prepared by using a mixture of sodium and copper di(2-ethylhexyl) sulphosuccinate as surfactants. In reverse micelles, at low water content (w=[H2O]/[AOT]<6), pure metallic copper particles are observed whereas at relatively high water content (w>6) the oxidation of metallic particles cannot be prevented. At w=10, pure copper oxide nanoparticles are observed. In gelified microemulsion (w=70), metallic nanoparticles are obtained. Their stability with time is rather long. Oxidation occurs after several days. This indicates a drastic change in the mechanism and rate of particle growth in the gelled systems as compared with those in reverse micelles. (C) 1997 Elsevier Science B.V.