Fabrication and morphology control of hollow polymer particles by altering core particle size

Particles with various morphologies were fabricated by changing the size of carboxyl-containing core particles and performing seeded emulsion polymerization as well as alkali posttreatment. The distribution of carboxyl groups, size, and morphology of the resultant particles were characterized with conductometric titration, dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Results indicated that the size of carboxyl-containing core latex particles could be varied from 95 to 240 nm by adjusting the concentration of sodium dodecyl sulfate (SDS). The percentage of carboxyl groups buried inside particles increased clearly along with the encapsulation of core by interlayer and shell polymers, and seeded emulsion copolymerization performed smoothly except the system using core particles with size less than 99 nm. After alkali posttreatment, the morphologies of corresponding particles showed porous, hollow, and bowl-like structure, respectively. Moreover, the relationship between core particle size and alkali-treated particle morphology was elucidated briefly.