Effects of particle sizes and dispersion media on micromolding of colloidal silica particles underneath top-gathering pillar patterns

Pyramidal assemblies of SiO2particles were fabricated by micromolding underneath top-gathering pillar arrays. The particles were molded densely with the decrease of the particle size. The particles dispersed in ethanol were packed closely under a top-gathering pillar unit, although some particles remained on the substrate without molding. From the in situ observation of drying the ethanol suspension, it was found the particles were molded by the convective forces, which were generated by the flux during the evaporation of ethanol.