Abstract:

Organo-inorgano nanocomposites with colloidal dimensions have interesting optical, catalytic, and mech. properties, particularly when such hybrids are reinforced with transition metal oxide nanoparticles. Nanoparticles with a mean size of 1.0-2.4 nm are obtained through hydrolysis of aluminum isopropoxide in the L2 phase of amphiphilic (PDMS-POE) polydimethylsiloxane-polyoxyethylene Silwet L-7607-octanol/acetylacetone-water mixts. The particle sizes are related weakly to the microemulsion compn.: 0.8-1.2 nm for 20 wt% Silwet L-7607 and 2.0-2.4 nm for 50 wt% Silwet L-7607. Protection of the particles against aggregation is ensured through their confinement in the intra-aggregate colloidal domains. Factors affecting the hydrolysis-condensation process of acetylacetone-complexed aluminum isopropoxide in copolymer-poor and copolymer-rich regions of PDMS-POE W/O microemulsions are studied by Fourier transform IR spectroscopy, small angle X-ray scattering, and transmission electron microscopy. Prepd. nanoparticulate dispersions possess long-term stability and form clear mixts. in different org. polar and nonpolar solvents. (c) 2002 Academic Press. [on SciFinder(R)]