Helical Columnar Self-Assemblies of Backbone-Chiral Polymers Bearing Mesogenic Side Groups with Enhanced Chiroptical Properties

Helical columnar self-assemblies present an attractive platform for chiroptical applications due to their structural versatility and well-established synthetic protocols. Conventional helical columnar polymers impose handedness through branched chiral side chains; however, the resulting steric frustration and conformational mismatch with racemic backbones often compromise supramolecular order and dilute helical chirality. Here, we introduce a backbone-chirality-driven design in cooperation with mesogenic side groups to construct homochiral helical columnar self-assembles. We first synthesized chiral polyesters functionalized with trialkoxy-terminated cyano-stilbene mesogenic side groups, which self-assemble into helical columnar liquid crystals, with handedness dictated by the chiral centers embedded in the backbone. Compared with side-chain-chiral analogues, backbone-chiral polymers demonstrate faster assembly kinetics and higher thermodynamic order, yielding absolute dissymmetry factors enhanced by up to 2 orders of magnitude. The backbone-chirality-directed helical columnar polymers display intense circularly polarized luminescence with tunable emission spanning cyan to red, including white light, through controlling excitation energy transfer processes. This strategy provides a general route to highly developed homochiral helical columnar polymers with promising applications in chiroptical technologies and flexible optoelectronic devices.