Synthesis of photoresponsive spiropyran-based hybrid polymers and controllable light-triggered self-assembly study in toluene

Abstract

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. A photoresponsive poly(spiropyran-containing methacrylate) modified with polyhedral oligomeric silsesquioxane (POSS) is synthesized by atom transfer radical polymerization (ATRP). Its self-assembly behavior is studied in toluene. Under the control of UV and visible light, it can reversibly self-assemble into aggregates because the closed spiropyrans transform to charged merocyanines, which form stacks that act as non-covalent crosslinking points and the POSS shell guarantees the stability of the aggregates. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.