Bioinspired solar membrane distillation guttation leaf with enhanced salt resistance and uniform vapor flux

Solar-driven passive multi-stage distillers present an efficient and low-cost strategy for alleviating water scarcity. However, when processing hypersaline seawater, they are affected by downstream crystallization and non-uniform vapor flux due to flow velocity attenuation along the flow path, especially in unidirectional flow distillers. Inspired by the hierarchical structure and guttation drainage pattern of plant leaves, we developed a biomimetic solar interfacial membrane distillation leaf that addresses these challenges. The design integrates a central vein with strategically distributed edge drippers to enable multi-directional brine discharge and to sustain a uniformly high-velocity flow field within the evaporator. This architecture prevents the easy salt saturation in downstream regions and suppresses the rapid crystal growth, thereby reducing the crystallized area by >30% compared with unidirectional evaporators. At the same time, it produces a more uniform vapor-flux field, mitigating the downstream decline in vapor production. As a result, a ten-stage leaf distiller achieves a remarkable gain output ratio of 2.17 at a feed salinity of 10 wt%. Field tests with natural seawater deliver up to a 15.7 kg/m²/d freshwater yield at a levelized cost of water of $3.54 USD/m³, demonstrating promising technical feasibility and economic potential under real-environment conditions. The proposed bioinspired guttation leaf offers a generalizable pathway to uniform-flux and high-salinity-resilient solar multistage membrane distillation for low-carbon, distributed desalination. © 2026 Elsevier B.V.