Successive growth and applications of polymeric particles with controllable size and shapes

Nonspherical particles resembling sea pineapples were synthesized by successive growth technique during soapless emulsion polymerization for various applications. First, highly cross-linked seed particle dispersion was synthesized by emulsifier-free emulsion polymerization with acrylic acid as co-monomer for the formation of surface carboxylic groups. Then, a successive growth scheme was applied to the seeds by swelling the particles with monomer droplets, followed by polymerization. The sea pineapple-shaped particles could be produced by adjusting the amount of monomer during the swelling step of the third growth. As a demonstrative application, the seed or sea pineapple-shaped particles could be used as templates for the synthesis of porous inorganic particles by spray drying technique. The resulting porous particles could be adopted as photocatalyst for the decomposition of organic molecules such as methylene blue. As another application, the dye molecules could be adsorbed onto the second grown particles to produce dye-doped nanospheres. Finally, the sea pineapple-shaped particles could be self-organized into supra-aggregates using toluene emulsions as confining geometries. Collectively, successively grown particles were found to be efficient building blocks to prepare the unusually packed structures or functionalized into colored products.