Flocculation‐resistant multimolecular micelles with thermoresponsive corona from dendritic heteroarm star copolymers

In this article, we report the self‐assembly of flocculation‐resistant multimolecular micelles with thermoresponsive corona from novel dendritic heteroarm star copolymers. The micelles have a core‐shell‐corona structure at room temperature according to pyrene probe fluorescence spectrometry, proton nuclear magnetic resonance (¹H NMR), transmission electron microscopy, and dynamic light scattering measurements. Increasing the temperature above the lower critical solution temperature (LCST), the micelles show high flocculation‐resistant ability resulting from a structure transition from core‐shell‐corona to core‐shell confirmed by a quantitative variable temperature ¹H NMR analysis method using potassium hydrogen phthalate as an external standard. A big volume change of the micelles is observed during the LCST transition. The drug loading and temperature‐dependent release properties of the micelles are also investigated by using coumarin 102 as a model drug, which displays a rapid drug release at a temperature above the LCST. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010