Helical Assembly of Long‐Chain Unsubstituted Poly( Para ‐Phenylene) Immobilized on Individual Cellulose Nanocrystals

The synthesis of chiral unsubstituted poly( para ‐phenylene) (PPP) chains has remained elusive for decades, with the production of high‐molecular‐weight PPP still inaccessible to date. Drawing inspiration from the intrinsic structural chirality of cellulose nanocrystals (CNCs), which plays a crucial role in their self‐assembly, we propose a novel strategy to address this synthetic obstacle by effectively immobilizing PPP on individual CNCs. This approach leverages intermolecular forces between CNC and PPP, including the CH–π interaction between the CH group of the pyranose ring and the aromatic ring of the PPP building block, as well as hydrogen bonds formed between the boronic acid groups of the PPP oligomers and the hydroxyl groups of the glucose units within the CNC structure, thereby facilitating the chirality transfer from CNCs to PPP chains. PPP immobilized on the CNC surface exhibits right‐handed intrachain helical self‐assembly and interchain helical π‐stacking, with the degree of polymerization reaching up to 80.2. This helical organization of PPP further laterally demonstrates the right‐handedness of individual CNCs in their undried state. Furthermore, suspensions, powders, and films composed of chiral CNC–PPP clusters exhibit pronounced fluorescence, structural coloration, chirality, and circularly polarized luminescence. This work opens novel insights and strategies for inducing chirality into polymer chains via transferring chirality from the nanoobject surface to prepare various chiral assemblies of nanoparticles or conjugated polymers.