Photo-responsive block copolymer mPEG-b-poly(Tyr)-g-NB was prepared by introduction of o-nitrobenzyl ester group into the side chain of amphiphilic poly(ethylene glycol)-b-poly(α-hydroxy acids) (mPEG-b-poly(Tyr)) containing pendent alkynyl group via copper-catalyzed azide-alkyne cycloaddition reaction. The amphiphilic mPEG-b-poly(Tyr) was synthesized via the ring-opening polymerization of O-carboxyanhydrides, with monomethoxy poly(ethylene glycol) (mPEG) as macroinitiator. The molecular structure, self-assembly, and photo-controlled release of the obtained mPEG-b-poly(Tyr)-g-NB were thoroughly investigated. mPEG-b-poly(Tyr)-g-NB could self-assemble into spherical micelles in water and showed disassembly under UV light irradiation, which was demonstrated by means of UV-vis spectroscopy, scan electron microscopes, and dynamic light scattering measurement. Fluorescence emission measurements demonstrated that Nile red, encapsulated by micelles, can be released upon UV irradiation. This study provides a convenient way to construct smart poly(α-hydroxy acids)-based nanocarriers for controlled release of hydrophobic drugs. Copyright © 2015 John Wiley & Sons, Ltd.

Light-responsive poly(carbonate)s PEG₁₁₃-b-PMPC_n-SP were synthesized via copper catalyzed azide-alkyne cycloaddition reaction between azide-modified spiropyran (SP-N₃) and amphiphilic copolymer PEG₁₁₃-b-PMPC_n. PEG₁₁₃-b-PMPC₂₅-SP can self-assemble to biocompatible micelles with an average diameter of ∼96 nm and a critical aggregation concentration of 0.0148 mg mL⁻¹. Under 365 nm UV light irradiation, the characteristic absorption intensity of merocyanine (MC) progressively increased and most of the micellar aggregations were disrupted within 10 min, suggesting the completion of the transformation of hydrophobic SP to hydrophilic MC. Subsequent exposuring the micelles to 620 nm visible light, spherical micelles aggregated again. The light-controlled release and re-encapsulation behaviors of coumarin 102-loaded micelles were further investigated by fluorescence spectroscopy. This study provides a convenient way to construct smart poly(carbonate)s nanocarriers for controlled release and re-encapsulation of hydrophobic drugs. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 750–760

Two novel dendrimer-derived compounds with pendant benzoxazine, named 0G benzoxazine (0G BOZ) and 1G benzoxazine (1G BOZ), were prepared using 0G poly(amido amine) (PAMAM) and 1G PAMAM, phenol, and paraformaldehyde. Effects of different generations of PAMAM on curing kinetics and thermal properties were investigated. Differential scanning calorimetric (DSC) measurements of the 0G BOZ and 1G BOZ were carried out at different heating rates of 5, 10, 15, and 20 K/min. Kinetic analysis by Kissinger's and Ozawa's method revealed the activation energy (E_a) of 0G BOZ were 109.1 and 109.3 kJ mol⁻¹, respectively, and those of 1G BOZ were 88.0 and 91.4 kJ mol⁻¹. The autocatalytic kinetic model was found to be the best description of the investigated curing reactions. In addition, the predicted curves from our kinetic models fit well with the nonisothermal DSC thermograms. Thermogravimetrical analysis of cured resin of 0G BOZ and 1G BOZ showed that the char yields of 0G BOZ and 1G BOZ were 37.6 and 26.3%, respectively. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013