Multi‐Modal Melt‐Processing of Birefringent Cellulosic Materials for Eco‐Friendly Anti‐Counterfeiting

Abstract Ubiquitous anti‐counterfeiting materials with a rapidly rising annual consumption (over 10 10 m 2 ) can pose a serious environmental burden. Biobased cellulosic materials with birefringence offer attractive sustainable alternatives, but their scalable solvent‐free processing remain challenging. Here, a dynamic chemical modification strategy is proposed for multi‐modal melt‐processing of birefringent cellulosic materials for eco‐friendly anti‐counterfeiting. Relying on the thermal‐activated dynamic covalent‐locking of the spatial topological structure of preferred oriented cellulose, the strategy balances the contradiction between the strong confinement of long‐range ordered structures and the molecular motility required for entropically‐driven reconstruction. Equipped with customizable processing forms including mold‐pressing, spinning, direct‐ink‐writing, and blade‐coating, the materials exhibit a wide color gamut, self‐healing efficiency (94.5%), recyclability, and biodegradability. Moreover, the diversified flexible elements facilitate scalable fabrication and compatibility with universal processing techniques, thereby enabling versatile and programmable anti‐counterfeiting. The strategy is expected to provide references for multi‐modal melt‐processing of cellulose and promote sustainable innovation in the anti‐counterfeiting industry.