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Superhydrophobic metallic surfaces made via pulsed laser ablation have been utilized recently. Immediately after laser ablation, metallic surfaces become hydrophilic. By aging the laser‐ablated surface in ambient air for a relatively long period of time (several weeks to several months) or using a chemical coating post process, this type of surface becomes superhydrophobic. Herein, a facile post‐process heat treatment that does not use any harsh chemicals is introduced to reduce the wettability transition time from hydrophilicity to superhdyrophobicity compared to surfaces treated for extended periods of time in ambient air. Grid patterns are ablated on aluminum, copper, and titanium by a nanosecond pulsed laser. Then, facile post‐process heat treatment is applied at different temperatures. The effect of temperature on the wettability transition time is studied. The transition time is reduced from several weeks/months to a few hours. The wettability transition mechanism for each metal is also explained. Additionally, several potential applications, such as self‐cleaning, water positioning, and water transport, are proposed.

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The world is facing a global issue of water scarcity where two-thirds of the population does not have access to safe drinking water. Water harvesting from the ambient environment has a potential equivalent to ∼10% of the fresh water available on the earth’s surface, but its efficiency requires a special control of surface morphology. We report a novel facile physicochemical hybrid method that combines femtosecond laser structuring with hydrothermal treatment to create a surface with a well-arranged hierarchical nanoneedle structures. Polydimethylsiloxane treatment of the thus-produced hierarchical structures nurtured superhydrophobic functionality with a very low water sliding angle (∼3°) and a high water adhesion ability. About 2.2 times higher water-collection efficiency was achieved using hierarchical structures over untreated flat Ti surfaces of the same area under a given experimental condition. The comparison of water-collection behavior with other samples showed that the improved efficiency is due to the structure, and wettability induced superior water attraction and removal ability. Moreover, a uniform water condensation under low humidity (28%) is achieved, which has potential applications in harvesting water from arid environments and in high-precision drop control.

The development of superhydrophobic metals has found many applications such as self-cleaning, anti-corrosion, anti-icing, and water transportation. Recently, femtosecond laser has been used to create nano/microstructures and wetting property changes. However, for some of the most common metals, such as aluminum, a relatively long aging process is required to obtain stable hydrophobicity. In this work, we introduce a combination of femtosecond laser ablation and heat treatment post-process, without using any harsh chemicals. We turn aluminum superhydrophobic within 30 minutes of heat treatment following femtosecond laser processing, and this is significantly shorter compared to conventional aging process of laser-ablated aluminum. The superhydrophobic surfaces maintain high contact angles greater than 160° and low sliding angles smaller than 5° over two months after the heat treatment. Moreover, the samples exhibit strong superhydrophobicity for various types of liquids (milk, coffee, CuPc, R6G, HCl, NaOH and CuCl 2 ). The samples also show excellent self-healing and anti-corrosion properties. The mechanism for fast wettability conversion time is discussed. Our technique is a rapid process, reproducible, feasible for large-area fabrication, and environment-friendly.