Fabrication of Hollow or Macroporous Silica Particles by Spray Drying of Colloidal Dispersion

In this study, hollow silica particles were fabricated by atomizing the dispersion of silica nanocolloids synthesized by modified Stober method and self-organization of the particles by spray drying technique. Rapid evaporation of the droplet containing the silica nanoparticles resulted in the formation of hollow microparticles at high evaporation temperature due to hydrodynamic instability of the droplet. Similar strategy was adopted for the fabrication of macroporous silica particles by the sol spray drying of the hetero-colloidal dispersion of polystyrene nanospheres and commercial silica nanoparticles. The morphologies of the porous particles were observed by scanning electron microscope with varying drying temperature. As a demonstrative purpose, the results using emulsion droplets as confining geometry was compared with the porous particles obtained from spray dryer. Collectively, spray drying was found to be more efficient manner to prepare the porous materials with continuous way in the view of production efficiency and time.