Templating effect of water-in-oil microemulsions for nanoparticles assembly in filament networks.

What is it about?

The incorporation of oil-dispersible superparamagnetic nanoparticles and water-dispersible gold nanoparticles in water-in-oil AOT microemulsions can modulate the microemulsion properties and create synergistic effects. By depositing a drop of a reverse microemulsion phase over a surface and allowing solvent evaporation, a hierarchical pattern of filament-like nanoparticle networks was found out. Several techniques were used to understand the mechanism involved in this template-mediated process of nanoparticle assembly. Therefore, UV-Vis, SAXS and XPS proved that an initial clustering of nanoparticles was occurring under the mediation of the surfactant. Elongation of microemulsion droplets was observed by cryo-SEM, contributing as a soft template for the subsequent assembly of the nanoparticles by linking cross-points of heteroclusters with remaining “free” nanoparticles. The resulting filament-like network as shown by TEM can be modulated with other factors such as water content and could contribute to the development of surface-assembled nanostructures on a larger scale.

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Why is it important?

A new templating-effect of reverse, water-in-oil microemulsions to afford surface-assembly of different types of nanoparticles in fiament-networks has been demonstrated.