All-Hydrophilic Micro-nanoporous Gradient Composites with Unidirectional Moisture Transport

The phenomenon of manipulated water transport demonstrated by insects and plants in natural biological systems has significant research implications for biological survival as well as for the development of advanced science and technology. It allows the penetration of minute quantities of liquid in one direction only, while blockage is achieved in the opposite direction, and it plays a key role in the field of intelligent liquid management. Although a great deal of research has been devoted to facilitating directional liquid transport by constructing bilayer hydrophilic/hydrophobic materials, the presence of hydrophobic regions limits the realization of continuous water transport. How to realize self-driven unidirectional flow within hydrophilic porous systems remains a pressing challenge. Herein, we developed fully hydrophilic micro-nanoporous gradient materials with directional liquid transport effects. The structural force difference between the contact interfaces is formed by depositing a hydrophilic nanoscale fiber membrane on the surface of a superhydrophilic micrometer-scale hydroentangled layer. The capillary force effect of the composite material is utilized to realize the directional transport of liquid and solve the limiting effect of the hydrophobic region. Through experimental verification and theoretical analysis, the mechanism of the directional water transport of the structure and its influencing factors are investigated. The proposed fully hydrophilic micronano porous gradient composite material shows promising applications in the field of sustainable textiles for directed sweat transport and biodegradable water collection devices, and is expected to be promoted in the development of other lipophilic diodes.