Two polyisoprene-block-poly(tert-butyl acrylate) (PI-b-PtBA) samples and a poly(tert-butyl acrylate) (PtBA) homopolymer (hPtBA) were prepared by anionic polymerization and characterized by light scattering, size exclusion chromatography, and NMR. The tert-butyl groups were removed from one of the diblocks to yield amphiphilic polyisoprene-block-poly(acrylic acid) (PI-b-PAA). PI-b-PAA was then used as the surfactant to disperse dichloromethane containing PI-b-PtBA and hPtBA at different weight ratios as oil droplets in water. Solid microspheres containing segregated polyisoprene (PI) and PtBA/hPtBA domains were obtained after dichloromethane evaporation. Permanent microspheres were obtained after PI domain crosslinking with sulfur monochloride. Porous microspheres were produced after the hydrolysis of PtBA and the extraction of the homopoly(acrylic acid) chains. The shape and connectivity of the poly(acrylic acid)-lined pores were tuned by changes in the PtBA/hPtBA content in the precursor microspheres. (C) 2003 Wiley Periodicals, Inc.