Surface morphology of core/shell particles and its determining factors

Abstract

Submicron-sized core/shell particles were prepared by polymerizing a mixture of methyl methacrylate and butyl acrylate in the presence of seeds of monodisperse polystyrene or its copolymer with methyl methacrylate. The influence of core/shell particle preparation conditions (method of shell formation, core composition, reaction temperature, introduction of surfactants, method of introducing monomers) on kinetics of the process, shape and surface morphology of the resulting particles is revealed. Depending on the abovementioned parameters, particles of various morphologies can be obtained, including both ones with a smooth surface layer and with a heterogeneous “golf ball-like” structure, while the presence of dents, as well as their size and the number can also be controlled by the synthesis conditions. The result of polymerization, that is, the morphology of core/shell particles and the formation of secondary particles, is established to be determined primarily by thermodynamic factors that take into account the distribution of shell-forming monomers in an equilibrium state.