Synthesis and properties of amphiphilic core-shell polymer microspheres

Monodispersed polymer microspheres with hydrophobic core and hydrophilic shell were prepared via a three-step method. Firsts polystyrene core was obtained through the emulsion polymerization. Subsequently, a relatively uniform shell containing butyl 4-vinylbenzenesulfonate was attached surrounding the core. The contents of the shell ranged from 10 similar to 40 %wt relative to that of the core. Finally, the sulfonate groups existing in the shell were converted into sulfonic acids through hydrolysis at elevated temperature, resulting in a highly charged hydrophilic shell. Infrared spectra (IR), transmission electron microscopy (TEM), differential thermal analysis, thermogravimetry (TGA) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the particle structure and chemical composition.