Coagulant‐Controlled Solvent Exchange Influences Multiscale Ordering in Cellulose Regeneration From Ionic Liquids

ABSTRACT

Cellulose regeneration from ionic liquids (ILs) proceeds through a nonequilibrium pathway in which solvent exchange, intermolecular interactions, and structural ordering are strongly coupled, yet the causal relationships among these processes remain incompletely understood. Here, we investigate how coagulant‐driven solvent exchange and coagulant‐specific intermolecular interactions jointly influence structural evolution during cellulose regeneration. By integrating time‐resolved polarized light microscopy, FT‐IR/2D correlation spectroscopy, and SAXS measurements over 0–60 min with molecular dynamics (MD) simulations, the regeneration process is examined across molecular‐to‐fiber scales. The combined results suggest that solvent exchange is associated with changes in intermolecular interactions and chain organization, accompanied by hydrogen‐bond reorganization. At the molecular level, a disorder‐to‐order transition in glucopyranose ring orientation is identified, suggesting a possible molecular link between interaction evolution and mesoscale structural development. The combined experimental observations suggest different regeneration trajectories in water and ethanol, associated with coupled differences in solvent‐exchange kinetics and intermolecular interactions. These results provide insight into how solvent exchange and intermolecular interactions jointly influence nonequilibrium ordering during regeneration, offering a multiscale framework for understanding and controlling processing–structure relationships in regenerated cellulose and related polymer systems.