Simulation Insights into the Mechanism of Water-Bridge Hydrogen Bonds (Cellulose–Water–Cellulose) Enhancing the Mechanical Properties of Cellulose Crystals

Abstract This study investigated the effect of defect-induced water penetration on the mechanical properties of cellulose crystals by using molecular dynamics simulation. In most previous studies, cellulose crystals were considered to be impermeable. However, this study indicates that chain-end defects provide a breakthrough for water molecules to penetrate into the cellulose crystals, allowing water molecules to form water bridges (water molecules that form hydrogen bonds with two cellulose chains simultaneously) between the cellulose molecule chains. Water bridges enhance the mechanical properties of cellulose. When more water molecules enter the space between the cellulose chains, the cellulose expands, and its mechanical properties weaken. This work provides a theoretical basis for understanding and accounting for the inevitable influence of chain-end defects on the mechanical performance of cellulose-based materials in their design and manufacturing processes.