Reversible CO2-, Photo- and Thermal Triple Responsive Supramolecular Chirality of Azo-Containing Block Copolymer Assemblies Prepared by Polymerization-Induced Chiral Self-Assembly

Polymerization-induced chiral self-assembly (PICSA) is an efficient strategy that not only allows the construction of the supramolecular chiral assemblies in a controlled manner but also can regulate the morphology in situ. Herein, a series of azobenzene-containing block copolymer (Azo-BCP) assemblies with tunable morphologies and polymeric supramolecular chirality were obtained through the PICSA strategy. The supramolecular chirality of Azo-BCP assemblies could be regulated by carbon dioxide (CO2) stimulus, and completely recovered by bubbling with Ar. A reversible morphology transformation and chiroptical switching process could also be achieved by the alternating 365 nm UV light irradiation and heating-cooling treatment. Moreover, the polymeric supramolecular chirality is thermal-responsive and a reversible chiral-achiral switching was successfully realized, which can be reversibly repeated at least five times. This work provides a feasible strategy for constructing triple stimuli-responsive supramolecular chiral nano-objects in situ.