2007 Volume 40 Issue 4 Pages 341-347
A thin film of silica nanoparticles with highly ordered hemispherical macropores and an ordering factor, ØVP6, of 98% was proved to be obtained by the Voronoi polygon analysis. Firstly, a monolayer of submicron polystyrene latex particles (PSL) with silica nanoparticles is obtained by coating a binary suspension of PSL particles and silica nanoparticles on a glass substrate using a spin coater. Secondly, the PSL particles are completely decomposed by calcining the coated films at 400°C for 10 min, affording a thin film of silica nanoparticles with hemispherical macropores. The size of the hemispherical macropores can be controlled from 136 to 506 nm by choosing PSL particles as a template. Although the monolayer of PSL particles without silica nanoparticles has several point and line defects, the PSL particle monolayer with silica nanoparticles has few defects. The small size of the silica nanoparticles is preferable for highly ordered hemispherical macropores. We propose a model that explains the ordering mechanism of particles during drying. The thin film of highly ordered hemispherical macropores can be used as a template for microcontact printing due to its hemispherical shape, or as an anti-reflective film due to its optical properties.