Cationic architecture engineering of amphiphilic ionic liquids for synergistic cellulose processing: From molecular...

Developing efficient solvent systems to overcome cellulose recalcitrance is pivotal for its valorization. While ionic liquids show promise, the role of cationic architecture in modulating solvation mechanisms remains underexplored. This study investigates a series of amphiphilic ionic liquids (AILs) with evolving cationic cores, from monocyclic imidazoles to bicyclic superbases (DBN, DBU), to elucidate their impact on cellulose processing. We identify a dual-action synergistic mechanism: the transition to superbase cores not only amplifies the basicity of chloride anions for hydrogen-bond disruption via charge delocalization but also enhances hydrophobic dispersion forces between the expanded cation and cellulose pyranose rings, preventing re-aggregation. Among these, [DBNC₁₀]Cl emerges as the optimal solvent, achieving rapid, complete dissolution due to its balanced basicity and viscosity. Regenerated films exhibit high transparency (∼87%), superior oxygen barrier properties, and mechanical strength comparable to engineering plastics (∼115 MPa). Furthermore, the process demonstrates sustainability through high solvent recovery (>91% after 15 cycles) and rapid biodegradability. This work establishes a molecular design principle for cationic engineering to tailor noncovalent interactions for high-performance cellulose materials.