Marine oil spills have induced severe water pollution and threatened sea ecosystems, which also result in a loss of energy resources. To deal with this problem, much work has been done for using superhydrophobic or superhydrophilic mesh for oil-water separation. Nevertheless, there are still great challenges in the rapid fabrication of extremely durable mesh with superwetting properties, particularly considering the highly efficient oil-water separation. In this study, we present a simple, efficient method to fabricate superhydrophilic and underwater superoleophobic stainless steel mesh surfaces with one-step femtosecond laser induced periodic nanoripple structures. The as-prepared mesh shows high separation efficiency, which is higher than 99% for various oil-water mixtures. More importantly, the wettability and the separation efficiency of the fabricated mesh show no obvious change after the abrasion tests and corrosion tests, indicating that the as-prepared samples possess robust stability. This study provides an efficient route for constructing durable and highly efficient separation mesh, which can be applied in the cleanup of large-scale oil spills in the near future.

Water scarcity is a serious global challenge, especially in arid and desert regions. Functional devices for directional water transport and fog collection have received increasing attention. Existing methods and technologies suffer from low fog-collecting efficiencies, complicated fabrication processes, and high fabrication costs. Herein, we report a simple and low-cost method to rapidly fabricate nanoparticle-covered microstructures on one side of a copper foam surface, using one-step femtosecond laser direct writing technology, which enormously improved processing efficiency. The resulting foam exhibits superhydrophilic/hydrophobic Janus properties. The foam allows water droplets to pass from the hydrophobic side to the superhydrophilic side, but not in the opposite direction. The Janus foam can therefore be used for harvesting water in fog environments, and the maximum water-collecting efficiency is 3.7 g cm h, which is much better than existing data. The Janus foam exhibits excellent stability during abrasion and hydraulic wash tests. This water-collecting design may provide an efficient route for overcoming future water shortages.

We report a simple, efficient method to fabricate micro/nanoscale hierarchical structures on one side of polytetrafluoroethylene mesh surfaces, using one-step femtosecond laser direct writing technology. The laser-treated surface exhibits superhydrophobicity in air and superaerophilicity in water, resulting in the mesh possessing the hydrophobic/superhydrophobic asymmetrical property. Bubbles can pass through the mesh from the untreated side to the laser-treated side but cannot pass through the mesh in the opposite direction. The asymmetrical mesh can therefore be designed for the directional transportation and continuous collection of gas bubbles in aqueous environments. Furthermore, the asymmetrical mesh shows excellent stability during corrosion and abrasion tests. These findings may provide an efficient route for fabricating a durable asymmetrical mesh for the directional and continuous transport of gas bubbles.

In this paper, we present a rapid and simple method to fabricate superaerophilic polytetrafluoroethylene cones via a two-step femtosecond laser direct writing technique, which enormously improved processing efficiency compared to the existing method. The laser-treated cones contained hierarchical microstructures and exhibited self-driven and directional transport of gas bubbles along the cones and away from the tip, even when the cones were horizontal. Furthermore, the laser-treated cones exhibited excellent chemical and long-term stability. This work may provide an effective and simple approach to obtain efficient manipulation of gas bubbles in practical applications.