Rapid and Persistent Suction Condensation on Hydrophilic Surfaces for High-Efficiency Water Collection.

Area of Science:

• Materials Science
• Surface Engineering
• Sustainable Technologies

Background:

• Water scarcity necessitates sustainable water collection methods.
• Dew condensation is a promising approach, but conflicting surface property requirements hinder efficiency.
• Existing methods struggle to optimize droplet nucleation, growth, and transport simultaneously.

Purpose of the Study:

• To develop an efficient water collection surface by mimicking moss structures.
• To overcome limitations of traditional condensation surfaces by enabling dropwise condensation on hydrophilic materials.
• To enhance water collection performance through a novel liquid suction mechanism.

Main Methods:

• Mimicry of *Rhacocarpus* moss structures to create a porous surface (RIPS).
• Implementation of a three-level wettability gradient on the RIPS.
• Utilizing a liquid suction mechanism to facilitate directional droplet transport.

Main Results:

• The RIPS demonstrated rapid, directional, and persistent droplet suction.
• Suction condensation enabled a low nucleation barrier, frequent surface refreshing, and controlled droplet shedding.
• Achieved a maximum of ~160% enhancement in water collection performance compared to hydrophobic surfaces.

Conclusions:

• The *Rhacocarpus*-inspired porous surface (RIPS) effectively achieves efficient water collection via suction-driven condensation.
• This approach overcomes the challenges of conflicting surface property requirements for different condensation stages.
• Provides a novel design route for engineered materials in water harvesting and phase-change heat transfer applications.