Preparation of silica nanoparticles catalysed by small organic tertiary amine and applications in surface coating with antireflective/antifogging properties

Herein, a facile strategy which is based on Stober method was presented in the preparation of sol-gel that contains silica nanoparticles with tunable diameter adopting small organic tertiary amine including trimethylamine, triethylamine and tri-n-propylamine (TPA) as the catalysts. The size of the resulting silica particles decreased sharply with extending the length of alkyl chain bonded on tertiary amine. The sub-10 nm silica nanoparticles were prepared while employing TPA as basic catalyst. Silica particles were characterized by transmittance electron microscopy, scanning electron microscopy and dynamic light scattering. Furthermore, after being coated by the as-prepared sol containing sub-10 nm silica particles, the glass substrate exhibited good antireflective property with the maximum transmittance as high as 96.2 % compared with that of the bare at about 91 %. Also, the coated glass showed good antifogging property. Finally, the underlying mechanism responsible for the formation of ultrasmall silica nanoparticles was proposed taking into account the steric barrier of protonated tertiary amine molecules anchored at silica nuclei surface by electrostatic interactions.