Large-Scale Fabrication of Wettability-Controllable Coatings for Optimizing Condensate Transfer Ability.

Systematic regulation of hydrophilic regions plays a key role in optimizing the heterogeneous hydrophilic-hydrophobic surface for promoting condensate transfer ability (CTA) under subcooling or high-humidity conditions. In this work, we develop an operable method to fabricate wettability-controllable coatings by regulating the mass ratio of superamphiphobic and superamphiphilic powder (MRP). By investigating the synergic relationship between CTA and MRP, we display an interesting competition between condensation and detachment of condensates. The initial dewing rate associated with reflecting phase change heat transfer capacity could be continuously strengthened by promoting MRP, while the detachment capacity with respect to improving the long-term condensing rate can be limited by the excessive superamphiphilic microregions. Based on this, we have optimized the threshold of MRP for promoting the condensation heat transfer ability and the water harvesting efficiency with the values of 10:0-8:2 and 10:0-4:6, respectively. This work provides important guidance in designing and optimizing heterogeneous hydrophilic-hydrophobic surfaces for multiple industrial applications including heat management, water harvesting, and desalination.