No abstract

The ordered arrangement of particles and holes in SiO 2 particle-accumulated films by small-angle X-ray scattering (SAXS) was investigated. The SAXS profiles of SiO 2 particles exhibited the typical oscillation shown by monodisperse spherical particles. On the other hand, the SAXS profile of the ordered SiO 2 particle-accumulated film showed an additional oscillation suggesting that another scattering component existed except for SiO 2 particles. Furthermore, considering two components: "SiO 2 in an air matrix" and "air holes in a SiO 2 matrix", we successfully reproduced the SAXS profile of the ordered particle-accumulated film. The additional oscillation shows the existence of the tetrahedral holes, suggesting that this SiO 2 particle-accumulated film forms a closepacked structure. The intensity of the additional oscillation increased with the regularity of the particle arrangement in the SiO 2 particle-accumulating film. These results suggest that SAXS measurements using synchrotron radiation can provide information on the order of particle arrangement in composite films.