Enhanced interfacial bonding strategy via the molecular encapsulation effect for durable superhydrophobic coatings

Abstract

Superhydrophobic coatings have attracted widespread attention for their high versatility and scalability in various water-involved application scenarios. Developing superhydrophobic coatings with excellent durability is important, yet extremely challenging. Since the interfacial bonding offered by the essential low-surface-energy property is too limited to maintain surface textures. Herein, a well-tailored strategy is proposed to address the interfacial weakness by introducing efficient adhesive functional moieties into the low surface energy polymer structures employed for constructing superhydrophobic coatings. Catechol and urea groups were selected as key functional moieties and were homogeneously dispersed within the silicone network by being constructed as crosslinkers. In addition, the urea moiety effectively suppressed the oxidation failure of the catechol moiety because of the molecular encapsulation effect which functioned through the hydrogen-bonded intermolecular interactions. Owing to the synergistic enhancement of the two adhesion functional moieties, the optimized superhydrophobic coating showed over fivefold boost in mechanical stability, tolerating 40 m of sandpaper abrasion and 250 cycles of tape peeling. Superhydrophobicity was also well kept after various harsh environmental tests including chemical corrosion, UV aging, and extreme temperatures. This novel approach indicates a feasible way to enhance durability and will contribute to the practical application of superhydrophobic coatings.