Preparation of Light-Responsive Polyester Micelles via Ring-Opening Polymerization of O-Carboxyanhydride and Azide-Alkyne Click Chemistry.

Reversibly light-responsive micelles are constructed from an amphiphilic azobenzene-containing diblock copolymer AZO-mPEG-poly(5)₂₅. The copolymer is synthesized via ring-opening polymerization of O-carboxyanhydrides bearing alkyne group, followed by azide-alkyne click chemistry with an azide-containing azobenzene derivative. AZO-mPEG-poly(5)₂₅ can self-assemble to spherical micelles. Light response of the polymeric micelles is demonstrated by UV-vis spectroscopy and scanning electron micro­scopy (SEM). SEM images show that after UV irradiation, the micelles are partly dissociated, which is ascribed to swelling of the hydrophobic chain because of hydrophobicity change during the trans-cis isomerization of the azobenzene group. After subsequent visible-light irradiation, the morphology returns back to micelles. [ABSTRACT FROM AUTHOR]