Regulating Chiral Helical Structures in Liquid-Crystalline Block Copolymers with Chiroptical Response by Synergistic Asymmetric Effects
Yijing Gan, Hongbin Dai, Yafei Ma, Xiaoxiao Cheng* （程笑笑）, Zhao Wang, and Wei Zhang*（张伟）
State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Engineering Laboratory of Novel Functional Polymeric Materials, Suzhou Key Laboratory of Macromolecular Design and Precision ynthesis, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
Macromolecules2022, 55, 8556--8565
Unraveling the chirality transfer mechanism is the key to governing chiral expression and structure−property relationships and further constructing new chiral functional devices. Herein, we have systematically investigated the chiral assembly, chiral transfer, and modulation of block copolymers (BCPs) at the molecular, supramolecular, liquid-crystalline (LC) phase, and macroscopic morphological levels. It is revealed that the
strength of the LC ordering of Azo mesogens, the solvophobic length of core-forming blocks, and the coupling effects between polymer side chains and backbones play important roles in the chiral evolution and shape change. Furthermore, the various morphologies with different shapes were achieved in the chirality transfer process, including spheres, nanofibers (worms and helical nanowires), vesicles, and more complex large compound micelles. The chiroptical response with morphological changes could be controlled by the in situ photoisomerization of the Azo units. This work provides new insights into designing self-assembled systems with tunable chirality and morphology and could advance the understanding of chiral transfer from molecules to polymeric aggregates.