Coupling Capture Efficiency and Liquid Transport via Geometry and Wettability Control in Fog Harvesting Surfaces

ABSTRACT Fog harvesting has emerged as an effective strategy for alleviating freshwater scarcity. Its performance is fundamentally governed by the coupled regulation of surface wettability distribution and structural parameters, which determine droplet capture, migration, and transport behaviors. In this work, a hierarchically patterned wettability‐controlled surface is developed, in which efficient coupling between droplet capture and directional transport is achieved through systematic tuning of pattern size, spacing, and transport pathway geometry. The results demonstrate that the synergistic interplay between structural parameters and wettability gradients markedly improves fog harvesting performance. The underlying mechanisms include improved droplet nucleation and capture, wettability‐gradient‐driven directional migration, and the establishment of continuous liquid transport pathways. Compared with uniform superhydrophobic surfaces and conventional structural designs, the optimized parameter configuration exhibits superior water collection performance. More importantly, the system suggests a transition from a droplet‐dominated collection regime to a more continuous mass transfer behavior, which may help mitigate the inherent trade‐off between droplet capture and liquid transport. These findings reveal that coordinated control of structural parameters and wettability distribution provides a robust route for systematically enhancing fog harvesting performance. This work offers a general parameter‐driven design strategy and mechanistic framework for high‐performance fog harvesting interfaces.