Preparation of monodispersed polymer microspheres by SPG membrane emulsification-solvent evaporation technology

The membrane emulsification coupled with solvent evaporation was adopted to prepare mono-dispersed polystyrene (PS) microspheres. Firstly, stable oil-in-water emulsion has been successfully obtained by pressing PS solution through SPG membrane into continuous phase at appropriate pressures. Then monodispersed PS microspheres with size of 2-20 mu m were obtained following the removal of solvent. The size of the PS microspheres was strongly dependent on the mean pore size of SPG membrane and concentration of PS solution. Furthermore, the effect of emulsion stability, operation pressure and emulsifier on the size and size distribution of microspheres were systemically investigated. Finally, the surface character of PS microspheres was examined via SEM.