A novel photo and thermo double-responsive block copolymer was developed to fabricate micelles and reverse micelles in aqueous solution. The block copolymer was synthesized by ATRP block copolymerization of a spiropyran-containing methacrylate (SPMA) with di(ethylene glycol) methyl ether methacrylate (DEGMMA). By facile control of the photo irradiation and solution temperature, PSPMA-core and PDEGMMA-core micelles can be obtained, respectively. The thermo-and photo-responsive micelles were used as smart polymeric nanocarriers for controlled encapsulation, triggered release, and re-encapsulation of model drug coumarin 102. The double-responsive self-assembly and disassembly were tracked by dynamic light scattering, transmission electron microscopy, and fluorescence spectroscopy. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 28552861, 2010