In Situ Controlled Construction of a Hierarchical Supramolecular Chiral Liquid‐Crystalline Polymer Assembly. (1st April 2020)

• Record Type: Journal Article
• Authors: Cheng, Xiaoxiao; Miao, Tengfei; Yin, Lu; Ji, Yujin; Li, Youyong; Zhang, Zhengbiao; Zhang, Wei; Zhu, Xiulin
• Is Part Of: Angewandte Chemie. Volume 132:Number 24(2020)
• Page Start: 9756
• Page End: 9764
• Publication Date: 2020-04-01
• Subjects: azobenzene -- helical fibrilar phase -- liquid-crystalline block copolymers -- polymerization -- supramolecular chirality; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202001657
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Hierarchical supramolecular chiral liquid‐crystalline (LC) polymer assemblies are challenging to construct in situ in a controlled manner. Now, polymerization‐induced chiral self‐assembly (PICSA) is reported. Hierarchical supramolecular chiral azobenzene‐containing block copolymer (Azo‐BCP) assemblies were constructed with π–π stacking interactions occurring in the layered structure of Azo smectic phases. The evolution of chirality from terminal alkyl chain to Azo mesogen building blocks and further induction of supramolecular chirality in LC BCP assemblies during PICSA is achieved. Morphologies such as spheres, worms, helical fibers, lamellae, and vesicles were observed. The morphological transition had a crucial effect on the chiral expression of Azo‐BCP assemblies. The supramolecular chirality of Azo‐BCP assemblies destroyed by 365 nm UV irradiation can be recovered by heating–cooling treatment; this dynamic reversible achiral–chiral switching can be repeated at least five times. Abstract : The PICSA concept (polymerization‐induced chiral self‐assembly) is demonstrated by constructing hierarchical supramolecular chiral azobenzene‐containing block copolymer (Azo‐BCP) assemblies in a controlled manner. The construction, dynamic reversibility, and morphological effect of supramolecular chirality in azo liquid‐crystalline assemblies are presented.