Formation of fractal structures upon the evaporation of nanoparticle dispersion droplets

摘要

The regularities of the self-organization of silver nanoparticles on solid substrates upon the evaporation of droplets of their aqueous dispersions were studied. The evaporation rate of the dispersion medium varied within a wide range. Upon a slow evaporation of the dispersion medium, a dense ring-like precipitate is formed around the droplet perimeter, where almost all particles are accumulated. In the vicinity of a rim, an ordered nanoparticle arrangement was observed. As the evaporation rate of the dispersion medium increases, most of the silver nanoparticles remain in the inner zone, limited by a rather dense rim, and form 2D fractal structures. At some regimes of droplet evaporation, 3D fractal structures were assembled whose shape depended on the substrate nature.