Mono-dispersed PMMA/GMA/DVB (PMGD) microspheres with size ranging from 200 to 800 nm were synthesized by soap-free emulsion polymerization and seeded soap-free emulsion polymerization. The as-prepared microspheres were aminated by ethylenediamine. Afterwards, different generations of dendritic PAMAM were grafted onto the surface of the microspheres by repeated Michael additions and amination reactions, at last different-sized water-dispersible microspheres with red fluorescence could be prepared by covalently coupling tetramethyl rhodamine isothiocyanate. Scanning electron microscopy and dynamic light scattering showed that the microspheres were very uniform. Fourier transform-infrared spectroscopy and elemental analysis demonstrated that the dendritic PAMAM had been successfully grafted onto the surface of the microspheres.

Key words: soap-free emulsion polymerization, seeded soap-free emulsion polymerization, mono-dispersed, dendritic PAMAM (d-PAMAM), fluorescent microsphere