Synthesis of Photoresponsive Spiropyran-Based Hybrid Polymers and Controllable Light-Triggered Self-Assembly Study in Toluene.

A series of polyhedral oligomeric silsesquioxane end-capped poly(spiropyran-containing methacrylate) (POSS-PSPMA) polymers, a kind of photoresponsive hybrid polymer, are synthesized via atom transfer radical polymerization. It is proved that the molecular weight of POSS-PSPMA is sharply increased by raising the proportion of methanol or the concentration of the reactants. The self-assembly behavior of POSS-PSPMA is studied in toluene: under the control of UV and visible light, POSS-PSPMA can reversibly self-assemble into aggregates because the charged merocyanines (MC) form stacks. These MC stacks act as non-covalent crosslinking points and POSS shell guarantees the stability of the aggregates. This system has a broad potential use in nanocarriers, especially for encapsulating and releasing polar substances in the nonpolar solvents. [ABSTRACT FROM AUTHOR]