Large-Scale Chiral Spherulites with Controllable Circularly Polarized
Luminescence in Liquid Crystal Block Copolymers Film
Abstract
Macroscopic chiral spherulites prepared by hierarchical self-assembly
have attracted considerable attention due to their excellent property as
chiroptical materials. However, preparing controllable handedness
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, we constructed chiral
controllable macroscopic spherulites with 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.