Synthesis of monodisperse, rodlike silica colloids with tunable aspect ratio

J Am Chem Soc. 2011 Mar 2;133(8):2346-9. doi: 10.1021/ja109524h. Epub 2011 Jan 21.

Abstract

Although the experimental study of spherical colloids has been extensive, similar studies on rodlike particles are rare because suitable model systems are scarcely available. To fulfill this need, we present the synthesis of monodisperse rodlike silica colloids with tunable dimensions. Rods were produced with diameters of 200 nm and greater and lengths up to 10 μm, resulting in aspect ratios from 1 to ∼25. The growth mechanism of these rods involves emulsion droplets inside which silica condensation takes place. Due to an anisotropic supply of reactants, the nucleus grows to one side only, resulting in rod formation. In concentrated dispersions, these rods self-assemble in liquid crystal phases, which can be studied quantitatively on the single particle level in three-dimensional real-space using confocal microscopy. Isotropic, paranematic, and smectic phases were observed for this system.

MeSH terms

  • Colloids / chemical synthesis
  • Colloids / chemistry
  • Particle Size
  • Silicon Dioxide / chemical synthesis*
  • Silicon Dioxide / chemistry
  • Surface Properties

Substances

  • Colloids
  • Silicon Dioxide