Solvent-Free Fabrication of Flexible and Robust Superhydrophobic Composite Films with Hierarchical Micro/Nanostructures and Durable Self-Cleaning Functionality

Abstract

Superhydrophobic surfaces hold tremendous potential in a wide range of applications owing to their multifaced functionalities. However, the mechanochemical susceptibility of such materials hinders their widespread usage in practical applications. Here, we present a simple, solvent-free, and environmentally friendly approach to fabricate flexible and robust superhydrophobic composite films with durable self-cleaning functionality. The obtained composite film features unexpected but surprising hierarchical micro/nanoscopic structures as well as robust superhydrophobicity with a water contact angle of similar to 170 degrees and a sliding angle below 4 degrees. Notably, the composite film exhibits mechanical robustness under cyclic abrasion, tape peeling, flexing, intensive finger wiping, and knife cutting; maintains excellent superhydrophobicity after long-time exposure to a high-humidity environment; and sustains exposure to highly corrosive species, such as strong acid/base solutions and organic solvents. The robust superhydrophobicity is ascribed to the induced micro/ nanohierarchical surface structures, resulting in the trapped dual-scale air pockets, which could largely reduce the solid/liquid interface. In addition, even after oil contamination, the composite film water repellency and self-cleaning functionality. The robust superhydrophobic composite film developed here is expected extend the application scope of superhydrophobic materials and should find potential usage in various industries and daily life.

Robust Hierarchical Porous PTFE Film Fabricated via Femtosecond Laser for Self-Cleaning Passive Cooling

“…Superhydrophobic surfaces are of wide interest, and they have made great progress in an extensive range of applications such as self-cleaning, anti-icing, anticorrosion, water–oil separation, and droplet manipulation. − Parts a and b of Figure show various optical images of the repulsion of the pristine and ablated PTFE films to various liquids. The droplet shapes of the four liquids, including water, milk, coffee, and glycerin, were nearly quarter-spheres or half-spheres on the pristine PTFE film (Figure a) and were almost spherical on the ablated PTFE film (Figure b), indicating the latter surface was capable of repelling the four liquids.…”

Laser Fabrication of Bioinspired Gradient Surfaces for Wettability Applications

“…The spine and barbs have micro/nano roughness. [44][45][46][47][48][49][50][51][52] Wettability can be evaluated by measuring the contact angle (CA) and sliding angle (SA) of a small liquid droplet on the target substrate. CA refers to the angle (θ) between the tangent of the air/liquid surface and the liquid/solid interface at the three-phase contact line when a droplet drops on a surface.…”

All-organic fluorine-free superhydrophobic bulk material with mechanochemical robustness and photocatalytic functionality

“…S7d and Movie 4, Supporting Information). [53,54] Dirt can be taken away from the bulk material surface by the sliding over water drops (Movie 5, Supporting Information).…”