Combination of Universal Chemical Deposition and Unique Liquid Etching for the Design of Superhydrophobic Aramid Paper with Bioinspired Multiscale Hierarchical Dendritic Structure

Abstract

It is urgent and significant for the further development of superhydrophobic materials to exploit a facile, low-cost, scalable, and eco-friendly method for the manufacture of superhydrophobic materials with self-cleaning, antifouling, directional transportation, and other characteristics. Herein, an outstanding superhydrophobic material composed of a flexible microconvex aramid paper substrate, micron-scale cone-shaped copper, micro−nanoscale dendritic copper oxide, and hydrophobic copper stearate film has been successfully constructed through delicate architectural design and a convenient preparation approach. Based on the microstructure evolution and composition analysis results, it is revealed that the cone-shaped copper was etched into a dendritic copper oxide structure step by step from the top to bottom and from the outside to inside in an alkaline liquid environment. Moreover, by virtue of the compositional features and structural characteristics, the constructed superhydrophobic material showcased a high contact angle (CA), low sliding angle (SA), high porosity, low surface free energy, and adhesion work. Meanwhile, the dendritic microstructure analysis, the calculation of solid−liquid interfacial tension, and the force analysis of water droplets jointly revealed the mechanism of the bounce and merged bounce of water droplets. Finally, this superhydrophobic material has the functions of self-cleaning, antifouling, and directional transportation, especially by controlling the deformation of the material to realize the transportation of water droplets in a specified direction.

Multifunctional Integrated Superhydrophobic Coatings with Unique Fluorescence and Micro/Micro/Nano-Hierarchical Structures Enabled by In Situ Self-Assembly

“…The numbers of bounces were all measured as 4 on the PDMS/RB-CDs/ZIF-8@OMMT surface within 200 ms (Figure g), while the PDMS surface did not exhibit any drop bounces (Figure f). The essence of the contact between the water droplet and PDMS/RB-CDs/ZIF-8@OMMT surface was its contact with the microporous/microsheet/nanoparticle tri-tier structures . As a result, the tri-tier hierarchical micro and nano structure had the characteristics of a nanoscale tip and thickness, the region where the water droplet contacts were divided into multiple parts by numerous nano/micro scale protrusions (Figure d).…”

“…The essence of the contact between the water droplet and PDMS/RB-CDs/ZIF-8@OMMT surface was its contact with the microporous/ microsheet/nanoparticle tri-tier structures. 57 As a result, the tritier hierarchical micro and nano structure had the characteristics of a nanoscale tip and thickness, the region where the water droplet contacts were divided into multiple parts by numerous nano/micro scale protrusions (Figure 5d). When a water droplet contacted the side of the hierarchical structure due to gravitational effects, the nanoscale branches with rich fluorinated groups could provide brace force as support points, as well as formed air layers trapped in the gap of the hierarchical structure.…”

Porous Gradient Composite with Dependable Superhydrophobic Protection for Multifunctional Electromagnetic Interference Shielding

“…The contact angle (CA) value of MF-NiP is 105.5° (Figure a), reaching the requirement of hydrophobicity (CA > 90°). Meanwhile, owing to the presence of air in the interstices of the double-sized GP and Fe 3 O 4 , the opposite force formed by air compression lifts the water droplets when they are depressed downward by gravity, forming the Cassie–Baxter condition …”

“…Meanwhile, owing to the presence of air in the interstices of the double-sized GP and Fe 3 O 4 , the opposite force formed by air compression lifts the water droplets when they are depressed downward by gravity, forming the Cassie−Baxter condition. 57 The hydrophobicity of the samples PGF-FL, PGF-GFFL-Ni, and PGF-FL-NiP treated by the spraying process was further improved, attaining a CA of more than 150°(Figure 7a). The surface wettability of PGF-FL-NiP was analyzed by evaluating the static and dynamic wettability.…”

Superhydrophobic Poplar Scrimber Via In Situ Synthesis of Cu7Cl4(OH)10·H2O Heterostructure Inspired by Pine Cone with Superultraviolet Resistance

“…Therefore, it is necessary for poplar scrimber to be modified against water to prolong its service life and broaden its application area. Several processes were proposed to make wood surface superhydrophobic, including a hydrothermal method, etching, , layer-by-layer self-assembly, − in situ growth, − and spraying. − Moreover, a skin-inspired design integrates mechanochemical-thermal robustness into superhydrophobic coatings, and a design of robust superhydrophobic surfaces was reported to improve the durability and lifetime of coatings. However, it was found that research has been mainly focused on a natural solid wood surface, with a very rare study on engineered wood surfaces such as poplar scrimber.…”