Analysis of moisture condensation on various uniform surfaces and biphilic microstructures
Year: 2026
Type: article
Abstract: The condensation of atmospheric water is of interest for many applications, including water harvesting, and has given rise to an abundant literature. However, conclusions are often contradictory as to the nature and morphology of the optimal surface. Some have concluded that hydrophilic surfaces are more favorable, others that hydrophobic or even superhydrophobic surfaces are optimal, and still others have reported improvements in condensation rates on biphilic surfaces with combined hydrophilic and hydrophobic wettability, but a comparison is not always possible between different publications. Using various technological processes, we have been able to realize biphilic surfaces with a wide variety of microstructures (10 μm to 500 μm) and surface roughnesses (R q in the 10 nm-200 nm range), resulting in a wide range of wettability parameters and behavior during the condensation phase. In this paper, we present a study of the condensation of humid air on all of these surfaces and show that the same condensation rate can be obtained on uniform or biphilic surfaces, regardless of their wettability and morphological parameters. A dew rate close to 100 mg/cm 2 /h is obtained in a 80% humidity/30 °C environment, that correspond to a subcooling of 12K. The resulting heat flux was deduced from experiments as a function of subcooling value and compared to condensation mechanism. It is in the range (150 W/m 2 - 1100 W/m 2 ) when increasing the subcooling from 6 K to 22K. Our results were compared with those found in the literature, with a focus on the influence of the diffusion layer resulting from the Non-Condensable Gases (NCG) in humid air. Our results show that higher roughness and 500 μm wide lines favor the dew rate by optimizing simultaneously dropwise condensation and water transport. Nevertheles, despite this partial conclusion, our results confirm that the impact of the surface morphology and wettability is limited by the smaller heat flux resulting from the diffusion layer, and surfaces should be optimized to control the air flow in order to circumvent its limitation.
Source: Hybrid Advances
Language: English
Subfield: Surfaces, Coatings and Films
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,540
OpenAlex ID: W7154372258