Core-shell microspheres made from glass beads as the core phase and polysulfone (PSf) as the shell phase can act as an absorbent in the separation process or a supporter for chemical reactions. Based on phase-inversion principles, a two-step sol-gel method was developed in this work in which ether was added first and H2O was added second to a PSf-containing dimethyformamide (DMF) solution to help PSf solidify on the surface of glass beads. The results from scanning electron microscopy, Fourier transform IR, and X-ray photoelectron spectroscopy showed that a dense layer of PSf (thin to several microns) was coated on the glass beads and the core-shell microspheres were almost monodispersed. The utilization percentages of the glass beads and PSf were high as 100 and 80%, respectively. The 0 thickness of the PSf membrane was calculated to be about 4.3 mu m. To obtain well-monodispersed microspheres, the practical volume ratio of ether to DMF was recommended to be larger than 4.5. The results suggested that the two-step sol-gel method is a highly efficient process for preparation of glass bead/PSf core-shell microspheres. (c) 2006 Wiley Periodicals, Inc.