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Synfacts 2007(6): 0598-0598  
DOI: 10.1055/s-2007-968585
Synthesis of Materials and Unnatural Products
© Georg Thieme Verlag Stuttgart · New York

Photoreversible Formation of Polymeric Micelles

Contributor(s): Timothy M. Swager, Wei Zhang
H.-i. Lee, W. Wu, J. K. Oh, L. Mueller, G. Sherwood, L. Peteanu, T. Kowalewski, K. Matyjaszewski*
Carnegie Mellon University, Pittsburgh, USA
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Publication History

Publication Date:
22 May 2007 (online)

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Significance

Atom-transfer radical polymerization (ATRP) of spiropyran (SP) monomer 1 in the presence of hydrophilic poly(ethylene oxide) (PEO) macroinitiator 2 provided PEO-b-SP copolymer 3, which was composed of 120 units of EO and eight units of SP, as determined by 1H NMR spectroscopy. In aqueous solution, polymer 3 self-assembled to form micelles. Irradiation with UV light (365 nm) led to photoisomerization and subsequent conversion of hydrophobic SP to hydrophilic merocyanine (ME), which completely disrupted the micelles. The photoinduced formation, disruption, and regeneration of the polymeric micelles were confirmed by atomic force microscopy (AFM). The photochemical control of encapsulation of the hydrophobic dye coumarin 102 was assessed by fluorescence spectroscopy.