A room temperature dissolution solvent and its mechanism for natural biopolymers: hydrogen bonding interaction investigation

Hydrogen bonds (HBs) are vital construction fundamentals of natural biopolymers. Investigating the hydrogen bonding interactions of biopolymers is crucial for the conformation, transformation, and construction of their functional materials. In this study, a theoretical dissection of HBs in biopolymers such as cellulose, starch, chitin, and silk was conducted for determining their internal interactions, which are classified as neutral HBs, coordination bonds, and anionic/neutral HBs. The binding energies of HBs were decomposed into electrostatic interaction, exchange-repulsion force, induction interaction, and dispersion interaction. According to theoretical calculations, a green and low-cost zinc chloride/formic acid eutectic solvent was synthesized for dissolving biopolymers. These results indicated that this eutectic solvent has universal applications in the dissolution of various biopolymers and can be used to elucidate their HB interaction mechanism and binding energy changes. This study will provide a theoretical strategy for enhancing the room temperature dissolution of biopolymers and promoting green chemistry and the use of sustainable bioresources.