A multifunction superhydrophobic surface with excellent mechanical/chemical/physical robustness

Superhydrophobic surfaces have many advantages in wetting fields. However, the lack of easyily production methods and limited mechanical/chemical/physical robustness remain the two most pertinent barriers to the scalability, large-area production, and widespread use of superhydrophobic materials. In this work, a mechanical/chemical/physical robustness superhydrophobic coating sample consisting of a regular array of square Cu mesh with secondary nano structures of polytetrafluoroethylene (PTFE) and SiO2 powders on the sidewalls is produced through a scalable and easyily production technique of the combination of hot-press sintering and subsquent spray-coating. The Cu mesh is used as a template to fabricate the grooves and bulges as the first-level roughness, and the SiO2 powder is maintained on the surface of the coatings to form two-level hierarchical structures, with both micro and nano structures firmly affixed by low-surface energy polymer binder (PTFE). For comparison, Cu mesh and Cu mesh/Cu sample are also produced. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and time-dependent apparent contact angle are used to examine the as-prepared materials. The corrosive solution, high temperature, UV irradiation, ultrasonic treatment, water drop hitting, sand drop impacting, multi-cycled sandpaper abrasion, tape-peeling test, and self-cleaning test was conducted to simulate the real-world damages. All of the armored superhydrophobic coating samples have an apparent water contact angle of more than 150 degrees, as well as outstanding mechanical and chemical resilience. The salt spray test and mechanical behavior of the as-prepared samples revealed that the armored superhydrophobic coating sample has the lowest corrosion rate, the highest tensile strength, and the greatest elongation among these three as-prepared samples, implying that it has the best anti-corrosion ability and mechanical property. This strategy might give guidance for the development of composite materials that need to retain mechanical/chemical/physical robustness in severe working conditions.

Automated summary

This study presents a scalable and easy production method to fabricate a mechanically/chemically/physically robust superhydrophobic coating sample. The coating sample consists of a Cu mesh, secondary nano structures of polytetrafluoroethylene (PTFE), and SiO2 powders, and exhibits high water contact angle and excellent mechanical and chemical properties. This research provides guidance for the development of composite materials that require robustness in severe working conditions.