Combining molecular dynamics and finite element modeling, a possible mechanism of the moisture-induced shape memory effect of wood cell walls is explored, emphasizing the role of interface mechanics, a factor previously overlooked. Upon wetting, the interface is weak and soft, and the material can be easily deformed. Upon drying, the interface becomes strong and stiff, and composite deformation can be locked. When the interface is wetted again and weakened, the previously locked deformation cannot be sustained, and recovery occurs. The elastic energy and topological information stored in the cellulose fiber network is the driving force of the recovery process.
- Chi Zhang
- Mingyang Chen
- Jan Carmeliet
