We synthesized a drug delivery system of poly (N-isopropylacrylamide)-b-oligo(methyl methacrylate) (PNIPAAm-b-OMMA) via polycondensation of two homopolymers in 1,4-dioxane. The products are characterized by FT-IR and H-1-NMR spectra and TEM. The PNIPAAm-b-OMMA copolymer micelles in aqueous solution present the same lower critical Solution temperature (LCST) as the unmodified PNIPAAm, owing to the formation of a core-shell micellar structure that the hydrophilic shell shields the hydrophobic inner OMMA core from interacting with water. The micelle carriers exhibit two heterogeneous microdomains: a hydrophobic inner core capable of highly solubilizing hydrophobic prednisolone molecules, plus a hydrated outer shell that stabilizes this micellar structure below its LCST. Moreover, the micelle carriers show reversible thermoresponsive aggregation/dispersion in response to temperature cycles through the LCST. By using the anti inflammation drug prednisolone as model drug, it is found that the PNIPAAm-b-OMMA drug carrier could prolong the release time and control the release amount by changing the temperature. Accordingly, this copolymer micelle may provide as an effective drug carrier for drug control and release. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 701-708,2009