Large-scale chiral spherulites with controllable circularly polarized luminescence in liquid crystal block copolymers film

Macroscopic chiral spherulites prepared by hierarchical self-assembly have attracted considerable attention due to their excellent property as chiroptical materials. However, preparing controllable chiral spherulites in bulk film remains a challenge due to the absent knowledge of the evolution mechanism from the molecule to macroscopic crystal during chiral assembly. In this contribution, chiral macroscopic spherulites were constructed with controllable circularly polarized luminescence (CPL) using enantiomeric tartaric acid and rhodamine B co-assembled with liquid crystal block copolymers, poly(ethylene oxide)-b-poly(methyl methacrylate) bearing azobenzene group side chains. It was found that the chiral liquid crystal field induced by exogenous chiral molecules was closely related to the formation of macroscopic chiral spherulites. Moreover, the transformation of azobenzene cis-trans isomerization under photo-thermal endows films with adjustable CPL. This facile strategy provides a platform to design large-scale chiral structures for chiroptical switching, encryption, and memory storage materials. Exogenous chiral molecules induce liquid crystal block polymer and fluorescent molecular hierarchical chiral assembly with controllable handedness and circularly polarized luminescence.image