Emulsion polymerization was used to prepare methylsilsesquioxane derivatives with an average particle size of 0.2−5.0 μm and various topological morphologies. Particles with an average particle size of 0.2−2.0 μm were prepared by emulsion polymerization using close to the critical micelle concentration of a nonionic emulsifier and a small amount of sodium hydroxide as a catalyst, whereas particles with an average particle size of 2.0−5.0 μm were obtained by suspension polymerization using a small amount of sodium hydroxide as a catalyst. Aggregation between the obtained particle colloids was not observed with the addition of an anionic emulsifier to the colloid solution at the earliest point in particle growth. A nonionic or cationic emulsifier was not effective, since the adsorption or diffusion of anionic emulsifier onto the particle colloids was accelerated due to the plus ζ potential of their surfaces.

A change in the morphological topology of particles of methylsilsesquioxane derivatives is observed with a change in the silicone monomer formulation. The particles change from a spherical shape to a hollow hemispherical shape with an increase in the content of silicaforming monomers in methylsilsesquioxane-forming monomers, whereas the spherical shape does not change with the addition of dimethyl silicone-forming monomers to methylsilsesquioxane-forming monomers. The intermediate shape is a sphere surrounded by a wrinkly surface, like a soccer ball, and the particle finally becomes a hollow hemisphere. These phenomena were examined by FT-IR, 29 Si CP/MAS NMR (solid-state), and XPS spectra from the perspective of internal steric stress due to tetra-or trifunctional units in the particle core.

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