Hierarchical Assembly of Amphiphilic POSS-Cyclodextrin Molecules and Azobenzene End-Capped Polymers

Macromolecules(2014), 47(16), 5739-5748.

Li Jinze, Zhou Zheng, Ma Li, Chen Guangxin, Li Qifang

Abstract: Stimuli-responsive polymers have been widely studied because of their potential use in nanocarriers and nanocontainers. In this study, a **art multistimuli responsive system was prepd. through a light controlled supramol. assembly. Mono cyclodextrin substituted iso-Bu polyhedral oligomeric silsesquioxane (mCPOSS), an amphiphilic mol., was synthesized by copper(I)-catalyzed azide-alkyne cycloaddn. (CuAAC), while azobenzene end-capped poly(ethylene glycol)-b-poly(2-(dimethylamino)ethyl methacrylate) copolymer (PEG-b-PDMAEMA-azo, PPA), a biocompatible pH/temp.-responsive macromol., was synthesized by atom transfer radical polymn. and CuAAC.  The self-assembly process of PPA and mCPOSS in aq. soln. was as followed: first, mCPOSS self-assembled into a nanosphere in aq. soln. because of its amphipathic property; then, the trans-azo end groups of the PPA interacted with the cyclodextrin cavities on the nanosphere, and complex micelles were formed by the supramol. assembly between PPA and mCPOSS.  In addn., the morphol. of the micelles could be adjusted by the ratio of PPA and mCPOSS, the formation and the dissocn. of the micelles could be controlled by visible and UV light, and the size of the micelles could be tuned by pH.