Study of the growth of ZnS nanoparticles in water/AOT/n-heptane microemulsions by UV-absorption spectroscopy

ZnS nanoparticles were synthesized at 25 degrees C using water-containing AOT reversed micelles as nanoreactors and characterized by UV-vis spectroscopy. The time dependence of the spectra emphasizes a slow rowing process of the ZnS nanoparticles coupled with a change of their photophysical properties. Both processes are well described by power laws. The nanoparticle size can be controlled by the molar ratio R (R = [water]/[AOT]), i.e. by the micellar size. The deposits obtained by evaporation of the volatile components of the microemulsions are found to be composed of a surfactant matrix containing ZnS nanoparticles smaller and more stable than that in the corresponding microemulsions. (C) 1999 Elsevier Science B.V. All rights reserved.