Development of superhydrophobic metallic surfaces with tuned morphology through microwave processing

The present study utilized microwave-based hydrothermal treatment to develop a durable superhydrophobic aluminium alloy (AA5083). The surface morphology was effectively tuned through modulation in processing temperatures with the transition from nanofibrils (NF) to densely networked flake-like (DNF) structures. Subsequently, the microwave processed sample surfaces (AA5083) were grafted with precursors of a silanizing agent (1H, 1H, 2H, 2H-Perfluorooctyltriethoxysilane). The silanization of nanostructured surfaces imparted superhydrophobicity (theta(s) >160 degrees), with low hysteresis (<10 degrees) and adhesion (40 mu N) observed for DNF. High adhesion (similar to 170 mu N) and hysteresis (>10 degrees) combined with low de-wetting resistance (theta(t)similar to 40 degrees) indicated metastable Cassie state for NFs owing to reduced longitudinal pinning and three-phase line sagging. As a result of the densely packed structures, the DNFs ensure low adhesion and hysteresis because of enhanced Laplace pressure. The mechanically stable DNFs showed high resilience to dynamic and impact loadings. Thus, microwave processing is a viable and efficient means of generating durable nanostructures for developing metallic superhydrophobic surfaces.

Automated summary

In this study, durable superhydrophobic aluminium alloy surfaces were successfully developed using microwave-based hydrothermal treatment. The surfaces exhibited low hysteresis and high resistance to adhesion, with densely networked flake-like structures showing enhanced wear and impact resistance.