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Covalent organic frameworks (COFs) with high porosity and well-organized channel structure are attractive candidates for advanced water treatment membranes. In their Communication (DOI: 10.1002/anie.201712816) H. Meng, J. Caro et al. present a two-dimensional imine-linked COF-LZU1 membrane with a thickness of only 400 nm supported on alumina tubes synthesized by an in situ solvothermal method. The membrane exhibits excellent water permeance and high rejection combined with outstanding water stability for water-soluble dyes with a size larger than 1.2 nm.

In article number 1704912, Yong Chen and co-workers demonstrate a biomimetic superhydrophobic microstructure inspired by the Salvinia molesta leaf using the immersed surface accumulation 3D-printing process. The controllable adhesive force can be easily tuned with a different number of eggbeater arms. The 3D-printed eggbeater structures have numerous applications including as microhands for droplet manipulation and microreactors, and for 3D cell culture, oil-spill clean-up, and oil/water separation.

Low roll-off angle, high impalement pressure, and mechanical robustness are key requirements for super-liquid-repellent surfaces to realize their potential in applications ranging from gas exchange membranes to protective and self-cleaning materials. Achieving these properties is still a challenge with superamphiphobic surfaces, which can repel both water and low-surface-tension liquids. In addition, fabrication procedures of superamphiphobic surfaces are typically slow and expensive. Here, by making use of liquid flame spray, a silicon dioxide–titanium dioxide nanostructured coating is fabricated at a high velocity up to 0.8 m s⁻¹. After fluorosilanization, the coating is superamphiphobic with excellent transparency and an extremely low roll-off angle; 10 µL drops of n-hexadecane roll off the surface at inclination angles even below 1°. Falling drops bounce off when impacting from a height of 50 cm, demonstrating the high impalement pressure of the coating. The extraordinary properties are due to a pronounced hierarchical nanotexture of the coating.

Superamphiphobic surfaces can repel both water and oils. Impalement pressure and mechanical stability are still challenges. Fabrication is typically slow or expensive. Using liquid flame spraying, an up-scalable method is demonstrated for fabricating SiO₂/TiO₂ nanostructured coatings at a velocity of 0.8 m s⁻¹. After fluorosilanization, the coating shows extremely low roll-off angles even toward n-hexadecane, high impalement pressure, and good transparency.