Fabrication of Micro-/Submicro-/Nanostructured Polypropylene/Graphene Superhydrophobic Surfaces with Extreme Dynamic Pressure Resistance Assisted by Single Hierarchically Porous Anodic Aluminum Oxide Template

Abstract

By applying a three-step anodic oxidation method followed by etching and pore widening treatment, etched micro-/submicroscale pits of ∼2 μm and ∼230 nm as well as anodized nanopores of ∼70 nm are combined to form hierarchically porous anodic aluminum oxide (HP-AAO) templates. Hierarchical micro-/submicro-/nanostructured polypropylene/graphene (HMSNS-PP/GP) superhydrophobic surfaces are laminated by a single HP-AAO template, exhibiting the similar arrangement, size, and shape with hierarchical papillae on lotus leaf surfaces. As expected, such a lotus-inspired HMSNS-PP/GP surface has an extremely small roll-off angle of ∼0.5° and a large contact angle of 155.0°, exhibiting high-efficiency self-cleaning characteristics. The HMSNS-PP/GP surface is endowed with static and dynamic wetting stabilities, which are reflected in immersion and impacting tests. After immersion, the HMSNS-PP/GP replica remains fully spotless accompanied with the ability to work under a hydrostatic pressure of ∼3626 Pa for at least 60 min. After impact, the maximum height of bounced droplets is up to 12.4 mm (i.e., 5.3 times the diameter of the droplet) at a Weber number of ∼32.12.

Overview of Engineering Carbon Nanomaterials Such As Carbon Nanotubes (CNTs), Carbon Nanofibers (CNFs), Graphene and Nanodiamonds and Other Carbon Allotropes inside Porous Anodic Alumina (PAA) Templates

“…There are some applications published using a PAA/graphene assembly [ 206 , 207 , 208 , 209 ] but in all of these cases a graphene transfer process is involved. This step can complicate the fabrication and induce reliability and reproducibility issues.…”

Microstructure and Hydrophobicity of PVDF-Based Films Prepared by Electrospinning Technique

“…In the past decades, many anti-icing or deicing materials have been developed. Among them, the superhydrophobic surfaces (quantified by a contact angle (CA, >150°) and roll-off angle (RA, <10°) wettability measurements) are a passive anti-icing technology, which not only can prevent ice accretion by avoiding water retention on the surface − but also can delay the freezing time, − thus greatly reducing the energy consumption of anti-icing. However, over time, supercooled raindrops will still freeze on the superhydrophobic surfaces, which are usually not conducive to deicing.…”

Stretchable superhydrophobic elastomers with on-demand tunable wettability for droplet manipulation and multi-stage reaction

“…31 Constructing SH surfaces relies on rough structures and low surface energies. 32 Therefore, multiple methods have been explored to create multiscale structures, including laser irradiation/etching, 33,34 compression molding with templates, [35][36][37] coating, [38][39][40][41] and particle filling. 42,43 However, each method has its own limitations; for example, it is challenging to achieve complicated microstructures with laser processing, an additional compression step is required for templating to avoid damaging the surface morphology during demolding, extra spray coating is needed to improve the durability over time, [44][45][46] or difficulties are experienced in controlling the surface morphology/adhesion force for particle filling.…”