Fu Morphological investigations of crosslinked polystyrene microspheres by seeded polymerization

W. Yang ) W. Ming ) J. Hu ) X. Lu S. Fu ( ) Department of Macromolecular Science and Laboratory of Molecular Engineering of Polymers Fudan University Shanghai 200433 China Abstract Crosslinked polystyrene microspheres with novel surface and inner morphologies were synthesized by seeded polymerization following a seed-swelling method, using uncrosslinked polystyrene microspheres as seeds and a mixture of toluene, styrene (St), and divinylbenzene (DVB) as the swelling agent. With the increasing toluene/ (St#DVB) ratio, the crosslinked particles changed from smoothsurfaced spheres to deformed spheres with dimples or heavy dents at the surface. A single hole inside the spherical particles was produced at low St/DVB ratio, while higher St/DVB ratios gave irregular dented or dimpled particles. Ultrathin crosssection observation by TEM revealed a non-uniformly crosslinked inner structure.