Self-assembly of centimeter-long micron-diameter fibers of isotropic spherical silica nanoparticles

Abstract

We present a novel evaporation-driven concept for self-assembly of centimeter-scale anisotropic mesostructures from isotropic nanoscale components in solution. These centimeters-long micron-diameter fibers are grown from an aqueous dispersion of 60 nm isotropic silica nanoparticles during the drying. We propose that water evaporation drives nanoparticle aggregation into porous structures, amplifying further evaporation and nanoparticle transport to fuel continuous fiber growth via a self-sustaining process. A theoretical model capturing the essence of the growth process closely matches experimental observations, suggesting the mechanism is likely nanoparticle-independent as interparticle interactions play a negligible role. This study introduces a new paradigm in self-organization, which is distinct from previous works relying on particle anisotropy or osmotic forces. Combining evaporation and nanoparticle dynamics opens exciting avenues for exploring and applying self-assembly in nanotechnology, promising novel materials with unique properties and functionalities.