Water loss can be delayed by trapping it within a polymeric network, i.e. hydrogel. However, the dynamic response of natural materials has not been explained to maintain water levels relatively constant against varying environmental conditions. In this study, patterned polymeric materials formed on plant seeds are observed to provide effective water retention ability against repeated dehydration-rehydration procedures. The perpendicular line pattern (layer-by-layer stack) of the polymer films induces lateral line patterns (surface lines) by a typical wrinkling mechanism, which contributes to the characteristic water interaction. The anisotropic line patterns on the seed surface generate more hydrophilic properties over the isotropic patterns against drying-out. The matric potential (Ψm) of water through the line patterned gel matrix generally shows higher efficiency over isotropically patterned gels. Anisotropic lines (i.e., wrinkles) are one of the most abundant patterning procedures, thus they are a more advantageous function occurring in natural systems. This study sheds light on material design technologies to control water interaction in porous materials for various applications.
Keywords: drying-resistance; hydrogel; patterns; plant seed; water transport.