Exploring hydrogen-bond structures in cellulose during regeneration with anti-solvent through two-dimensional correlation infrared spectroscopy

Cellulose, renowned for its excellent biocompatibility, finds extensive applications in both industrial and laboratory settings. However, few studies have specifically addressed the mechanistic evolution of hydrogen bond networks in cellulose during the dissolution and regeneration processes. In this research, the regeneration mechanism of cellulose in water and ethanol is investigated through molecular dynamics simulations. The results indicate that the ability of water molecules to disrupt hydrogen bonds between cellulose and ionic liquids is stronger than that of ethanol, which is more conducive to promoting the regeneration of cellulose. Besides, the Fourier transform infrared spectroscopy coupled with two-dimensional correlation infrared spectroscopy techniques are employed to unveil the evolution sequence of hydrogen bonds during dissolution and regeneration: ν(OH) (absorbed water) → ν(O3-H3···O5) (intrachain) → ν(O6-H6···O3') (interchain) → ν(O2-H2···O6) (intrachain) → ν(OH) (free). This study not only enhances our understanding of the intricate hydrogen bond dynamics in cellulose dissolution and regeneration but also provides a foundation for the expanded application of cellulose in diverse fields.