Structural Pattern Formation of Composite Particles with CeO₂ and Polymer Brushes

The particle dispersibility in organic solution is important to fabricate a self-assembly film with ordered structure. In this study, surface modification of CeO₂ nano particles with high-density poly-methyl methacrylate (PMMA) brushes was conducted to improve its dispersibility and tried to make the self-assembly film of these polymer-inorganic composite particles.
The CeO₂ composite particles with PMMA brushes (PMMA-CeO₂) showed a good dispersibility in organic solvents. The particle structure of PMMA-CeO₂ was investigated by ultra small-angle X-ray scattering measurement and it was confirmed that its shape was almost a hard-sphere. The self-assembly film with PMMA-CeO₂ was fabricated by drop cast method and observed by the scanning electron microscope. The monolayer film of PMMA-CeO₂ with close-packed structure was fabricated via the chain structure depending on the volume fraction of PMMA-CeO₂ in solution. Furthermore, at quite low volume fraction, it was suggested that PMMA-CeO₂ were isolated at equal intervals with hexagonal coordination.