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.

亲水区域的系统化调控，对于优化异质亲水-疏水表面以提升过冷或高湿环境下的冷凝液传输能力（condensate transfer ability, CTA）具有关键作用。本研究开发了一种可操作的制备方法，通过调控超双疏（superamphiphobic）与超双亲（superamphiphilic）粉体的质量比（MRP）来制备润湿性可控的涂层。通过探究CTA与MRP之间的协同关系，本研究揭示了冷凝过程与冷凝液脱附过程间存在有趣的竞争效应：反映相变传热能力的初始结露速率，可通过提升MRP得到持续增强；而提升长期冷凝速率所需的脱附能力，则会因过量的超双亲微区域受到抑制。基于此，本研究优化了用于提升冷凝传热能力与集水效率的MRP阈值，二者对应的最优区间分别为10:0–8:2与10:0–4:6。本研究为异质亲水-疏水表面的设计与优化提供了重要指导，可应用于热管理、集水及海水淡化等多个工业场景。