Multifunctional integrated pattern for enhancing fog harvesting water unidirectional transport in a heterogeneous pattern

Solid surfaces with improved wettability as well as geometric structures can enhance capture and droplet removal, thereby improving fog harvesting. We fabricated Al wires by combining superhydrophilic (SHL), superhydrophobic (SHB), and oil-infused SHB (SHBO) surfaces into a pattern whose fog-harvesting efficiency could be measured. The SHL-SHBO-SHL pattern showed the highest promise of water droplet capture and mobility on a solid surface with 42% efficiency compared to the 34% efficiency of Bare. In order to identify the optimal efficiency features, two boundary conditions (boundary I: from SHL to SHBO and boundary II: from SHBO to SHL) were introduced, and the impact of the hydrophilic area was examined. Boundary I boosts capture efficiency whereas boundary II increases drain efficiency. Understanding the forces operating at the wettability gradient surface, as well as incorporating the area ratio of SHL and SHBO via wettability combinations, are key to designing effective fog harvesting systems.