Regulating Chiral Helical Structures in Liquid-Crystalline Block Copolymers with Chiroptical Response by Synergistic Asymmetric Effects

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.

Automated summary

This study systematically investigated the chiral assembly, chiral transfer, and modulation of block copolymers at different levels, revealing the importance of LC ordering strength, core-forming block solvophobic length, and coupling effects between polymer side chains and backbones in chiral evolution and shape change. Various morphologies with different shapes were achieved in the chirality transfer process, providing new insights into designing self-assembled systems with tunable chirality and morphology.