Size-Controlling Synthesis of Narrowly Distributed Particles of Methylsilsesquioxane Derivatives

Abstract

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.