Veratraldehyde-Derived Poly(phenol imidazole) Nanosheets for Thermally Stable UV-Shielding Poly(vinyl alcohol)...

Developing nanomaterials from lignin and its derivatives represents an effective strategy for the high-value utilization of lignin; however, achieving template-free morphological control of lignin-based nanomaterials remains a significant challenge. Herein, we propose a strategy combining Scholl and demethylation reactions for the preparation of lignin-derived nanosheets using veratraldehyde-derived triarylimidazoles as the precursor. Oligomerization is achieved through the Scholl reaction of aromatic ring moieties, concurrent with the conversion of methoxy moieties to phenolic hydroxyl groups via demethylation.This dual mechanism enables the monomers to assemble into poly(phenol imidazole) nanosheets with a thickness of 5 nm, mediated by both covalent polymerization and noncovalent interactions. By incorporating these nanosheets into a poly(vinyl alcohol) matrix, the mechanical properties, thermal stability, and UV-shielding capabilities of the resulting composites are simultaneously enhanced. This work provides valuable insights into the high-value valorization of lignin and offers a novel template-free synthesis strategy for low-dimensional organic nanomaterials.