Bioinspired superhydrophilic-hydrophobic integrated surface with conical pattern-shape for self-driven fog collection

Area of Science:

• Materials Science
• Surface Engineering
• Fluid Dynamics

Background:

• Fog deposition and transport on asymmetric surfaces are crucial for water harvesting.
• Simultaneously achieving fast fog deposition and rapid droplet transportation on engineered surfaces remains a significant challenge.

Purpose of the Study:

• To design and fabricate a novel surface capable of efficient fog collection.
• To investigate the fog collection efficiency of a superhydrophilic-hydrophobic integrated conical stainless steel needle (SHCSN).

Main Methods:

• Fabrication of SHCSN inspired by cactus spines and desert beetles.
• Utilizing theoretical modeling and experimental exploration to optimize surface properties.
• Measuring droplet transportation velocity and fog harvest efficiency.

Main Results:

• The SHCSN surface demonstrated enhanced fog deposition on hydrophobic regions and rapid transport on superhydrophilic regions.
• Droplet average transportation velocity on SHCSN exceeded that of other surfaces due to Laplace pressure and self-driven phenomena.
• Optimized SHCSN achieved superior fog collection efficiency compared to uniform superhydrophilic or hydrophobic/superhydrophobic surfaces.

Conclusions:

• The SHCSN presents a highly efficient solution for fog collection by integrating distinct surface properties.
• The design overcomes limitations of previous surfaces by enabling simultaneous fast deposition and rapid transport.
• This technology holds promise for improving water harvesting in arid and fog-prone regions.