Scalable-Manufactured Superhydrophobic Multilayer Nanocomposite Coating with Mechanochemical Robustness and High-Temperature Endurance.

Abstract

Artificial superhydrophobic coatings with mechanical stability, chemical stability, and strong adhesion have been achieved separately. However, a simultaneous demonstration of these features along with stability to high-temperature exposure is challenging. Herein, inspired by the micro/nanoscale hierarchical superhydrophobic surfaces of solid cactus plants, we propose a novel plasma-enhanced high temperature liquid-phase-assisted oxidation and crosslinking (PHLOC) in-situ co-growth strategy to design superhydrophobic nanocomposite coatings on metals based on organic-inorganic multilayer structures in which PTFE nanoparticles cross-linked to form a compact top layer with hierarchical surface textures on a ceramic skeleton with a papilla array, integrating multiple robust wettability characteristics with mechanochemical strength to isolate the underlying materials from the external environment. Remarkably, the superhydrophobic coating exhibits strong mechanical robustness undergoing the 120th linear abrasion or 40th rotary abrasion cycle and can be applied on large area and arbitrary shapes of metal substrates. Moreover, the samples sustain exposure to highly corrosive media, namely, aqua regia, sodium hydroxide solutions, and simulated seawater solution, to reflect long-term chemical robustness. More importantly, the multilayer coating demonstrates excellent high-temperature endurance, thermal cycling stability of 500 °C, and thermal repairability of superhydrophobicity. With multifaceted robustness and scalability, the superhydrophobic multilayer coating should find potential usage in the field of high-tech equipment with severe alternating or impact loads, high-temperature service, and chemical corrosion.