Boiling water treatment for wettability improvement of aluminum fin surfaces

This work reports the effectiveness of a simple and rapid method for wettability improvement on aluminum surfaces - boiling water treatment. The wetting behavior and drainage performance on a series of aluminum surface samples after different lengths of boiling water treatment (3 minutes, 5 minutes, and 10 minutes) are examined. The data of contact angles for different sizes of droplets placed on these samples are reported with detailed surface roughness information from a 3D optical surface profiler. The contact angles are observed to decrease from the original value of 94.5° to approximately 10° after 10 minutes of treatment, and the reduction is correlated with the treatment length. Scanning electron microscopy (SEM) images and 3D optical profiler images suggest that the boiling water treatment facilitates oxidation of the sample surface and greatly alters the micro-structures on the surface, which are believed to be the two main reasons to change the droplet wetting behavior. The contact angle measurements are conducted again two days after the treatment and the hydrophilicity is retained.