Accurately controlling the shell thickness in the core–shell microspheres with single silica core and poly (butyl acrylate) rubber shell via emulsion polymerization

Abstract

The shell thickness of core–shell microspheres with a rigid core and soft rubber shell has been accurately controlled through the emulsion polymerization. When the amount of BA monomer and SiO2 is fixed, the morphology of core–shell microspheres with SiO2 core (Φ = 280 nm) and poly (butyl acrylate) (PBA) shell varies along with the emulsifier concentration (Ce). If Ce is lower than a low critical value Cel, aggregated micelles with multiple SiO2 cores are formed. And while Ce is higher than an upper critical value Ceu, isolated PBA micelles without SiO2 core appear in the system. For a given amount of BA monomer and SiO2 core, core–shell particles with single SiO2 core can only be obtained at Cel Ʃ > ƩLC), the rubber shell thicknesses of core–shell particles with single SiO2 core can vary from 8 to 57 nm along with the weight ratio of BA monomer to SiO2 that increases from 1:10 to 1:1.