Many advanced materials are designed for separation of immiscible oils/ organic solvents and aqueous solutions, including poly(vinylidene fluoride) (PVDF) based materials with superwettability. However, due to the limited solubility of PVDF, techniques (e.g., phase inversion and electrospinning) often involve the use of toxic organic solvents. Here a facile organic solvent free method is described to prepare a porous PVDF-MWCNT (multiwalled carbon nanotube) foam using table salt as a sacrificial template. The porous PVDF-MWCNT foam is characterized as superhydrophobic-superoleophilic with good elasticity due to its 3D porosity and low surface energy. The foam exhibits high adsorption capacity to a variety of oils/organic solvents and can be easily reused by squeezing, heating, or releasing in other solvents. More over, the foam is highly resistant toward UV exposure, corrosive aqueous solutions such as acidic, alkaline, salty solutions, and turbulent environ ments, and shows effective oils/organic solvents removal in these complex environments. The continuous separation of immiscible oils/organic solvents and corrosive aqueous solutions with vacuum assistance is also presented. The organic solvent free and reusable PVDF-MWCNT foam is a promising candidate for large scale industrial separation of oils/organic solvents and water in corrosive and turbulent conditions.

The fabricated superhydrophobic–superoleophilic mesh is bent into a V-shape-channel to guarantee floating oils are always in contact with the mesh.

Robust superamphiphobic coatings fabricated by a facile chemical deposition and low surface energy modification were coated on both hard and soft materials to repel water and oils.

Spontaneous pumpless transportation (SPT) of liquids has generated tremendous demands in microfluidic systems and advanced devices. However, the transportation of nonpolar organic liquids on open platforms underwater remains a challenge because most existing SPT systems are only designed for use in air. Here, we report a surface-tension-driven SPT system to transport various nonpolar organic liquids using underwater extreme wettability patterns. The patterns were fabricated with a wedge-shaped superoleophilic track on a superoleophobic background by combining CuCl2 etching, stearic acid modification, and mask-based nitrogen cold plasma treatment. Three types of underwater SPT processes-horizontal transport, tilted transport, and directional transport-were studied experimentally and theoretically. For horizontal SPT and tilted SPT, the capillary force was the main driving force, which depended on the wedge angle of the superoleophilic track. The excellent transportation ability of horizontal SPT of underwater liquid droplets was obtained at a wedge angle of 3-5°. The maximum moving height of organic liquids on the tilted SPT transport was obtained at an angle of 8°. For directional SPT, organic liquids did not drop off in the moving process because of the constraint imposed by surface tension, resulting in the sustained directional transport with long distances and complex trajectories.

Oil/water separation has been addressed by various materials characterized with superwettability, but most of the methods involve corrosive or toxic chemicals which will cause environmental concerns. Proposed herein is an environmentally friendly method to realize oil/water separation. Nylon mesh is exposed to atmospheric pressure plasma for surface modification, by which micro-/nanostructures and oxygen-containing groups are created on nylon fibers. Consequently, the functionalized mesh possesses superhydrophilicity in air and thus superoleophobicity underwater. The water prewetted mesh is then used to separate oil/water mixtures with the separation efficiency above 97.5% for various oil/water mixtures. Results also demonstrate that the functionalized nylon mesh has excellent recyclability and durability in terms of oil/water separation. Additionally, polyurethane sponge slice and polyester fabric are also functionalized and employed to separate oil/water mixtures efficiently, demonstrating the wide suitability of this method. This simple, green, and highly efficient method overcomes a nontrivial hurdle for environmentally safe separation of oil/water mixtures and offers insights into the design of advanced materials for practical oil/water separation.

Water harvesting is used for transforming moisture into available water resources in regions that suffer water scarcity.

Robust superhydrophobic surfaces were synthesized as composites of the widely commercially available adhesives epoxy resin (EP) and polydimethylsiloxane (PDMS). The EP layer provided a strongly adhered micro/nanoscale structure on the substrates, while the PDMS was used as a post-treatment to lower the surface energy. In this study, the depositions of EP films were taken at a range of temperatures, deposition times, and substrates via aerosol-assisted chemical vapor deposition (AACVD). A novel dynamic deposition temperature approach was developed to create multiple-layered periodic micro/nanostructures that significantly improved the surface mechanical durability. Water droplet contact angles (CA) of 160° were observed with droplet sliding angles (SA) frequently <1°. A rigorous sandpaper abrasion test demonstrated retention of superhydrophobic properties and superior robustness therein, while wear, anticorrosion (pH = 1-14, 72 h), and UV testing (365 nm, 3.7 mW/cm, 120 h) were carried out to exhibit the environmental stability of the films. Self-cleaning behavior was demonstrated in clearing the surfaces of various contaminating powders and aqueous dyes. This facile and flexible method for fabricating highly durable superhydrophobic polymer films points to a promising future for AACVD in their scalable and low-cost production.

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