Synergistic Effect of Neighboring Superhydrophilic Patterns on Superhydrophobic Surfaces for Enhanced Fog Collection.

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In this work, a superhydrophobic surface loaded with elliptical superhydrophilic patterns in a V-shaped arrangement has been fabricated with the help of shape memory membranes with uniform vertically penetrative channels (i.e., SMEUVs, as a mask). The special geometry (elliptical) and arrangement (V-shaped) of superhydrophilic patterns play important roles in the enhancement of fog collection. The former not only facilitates droplet detachment from superhydrophilic regions but also dominates its directional transport. The latter promotes the coalescence of tiny droplets based on directional flow pathway toward collection area, minimizing the risk of re-evaporation of them and providing fresh sites for subsequent nucleation and growth of droplets. The combination of them contributes to the synergistic effect of neighboring superhydrophilic patterns on the superhydrophobic surface. As a result, the optimal specimen (V-shaped arrangement of elliptical superhydrophilic patterns) in this work exhibits much higher fog collection efficiency (∼4 times) relative to the reference (superhydrophobic or superhydrophilic surface). Our results are significant for the design and fabrication of fog collection systems.