Hierarchical Micro/Nanostructured Diamond Gradient Surface for Controlled Water Transport and Fog Collection

Abstract

The directed transport of liquids is essential for numerous applications, such as microfluidics, heat transfer, and water harvesting. However, the traditional chemical coatings used for topographical or chemical gradients lack chemical stability and long‐term durability in harsh environments, such as elevated humidity, high temperature, or high pressure. Here, multifunctional robust diamond gradient films with gradually changed multilevel structure and chemical composition are designed and synthesized via a controlled chemical vapor deposition process. The size and abundance of hierarchical micro/nanostructural diamond crystals gradually increase along the film's length by manipulating deposition temperature and gas‐phase concentration, which endows the gradient surface with the ability to direct water droplets from the highly hydrophobic diamond‐rich surface (contact angle 141°) toward the hydrophilic SiC surface (contact angle 13°). This unique property is used to promote water condensation in seawater desalination systems with high humidity; significantly, the fog‐collecting ability is three times higher than that of the hydrophobic film and eight times higher than that of hydrophilic film. More importantly, the water harvesting performance remains even after harsh treatments with corrosive liquids and abrasive sandblasting, indicating potential applicability in microfluidics, desalination, and fog collection.

Solar‐Driven Airflow‐Enhanced All‐Daytime Solar Steam Generation Based on Inverse‐Bowl‐Shaped Graphene Aerogels

“…We would like to point out that the water collection rate could be further increased by optimizing the condenser. For example, recently, Wang et al [ 51 ] designed and synthesized a multifunctional robust diamond gradient film with a gradually changed multilevel structure and chemical composition, which has the ability to guide water droplets from a highly hydrophobic diamond‐rich surface to the hydrophilic SiC surface, promoting water condensation. The optimization on the condenser for purified water collection will be explored in our future work.…”

A Review of High-Energy Density Lithium-Air Battery Technology: Investigating the Effect of Oxides and Nanocatalysts

“…e catalyst reduces the activation energy, so it plays an essential role in reducing the potential. Because the effect of catalysts is completely surface-related, nanomaterials are very effective because they have a high surface-to-volume ratio [155][156][157][158][159]. Furthermore, due to the nanometer dimensions of the cathode cavities, nanocatalysts must be used, whether we like it or not.…”

Bio-Inspired Hierarchical Micro-/Nanostructures for Anti-Icing Solely Fabricated by Metal-Assisted Chemical Etching

“…The hierarchical micro-/nanostructure is crucial to the superhydrophobic property because the composite surface consists of solid surfaces and air pockets, which increases the contact angle of water [ 20 , 21 ]. Currently, hierarchical micro-/nanostructures consisting of different materials such as Si [ 22 ], SiO 2 [ 23 ], TiO 2 [ 24 ], SnO 2 [ 25 ], MgO [ 26 ] are being demonstrated and applied in superhydrophobic [ 27 ], self-cleaning [ 28 ], fog collection [ 29 ], oil-water separation [ 30 ], anti-icing [ 31 , 32 ], energy [ 33 , 34 , 35 , 36 ], and sensing [ 37 ] applications.…”