Facile fabrication of superhydrophobic surfaces via spraying with silicone-urea copolymers

The microphase separation method is recognized as one of the most promising approaches to fabricate superhydrophobic surfaces (SHS), but it is still subjected to confined polymer materials, expensive instruments, and complicated techniques. Here we innovatively proposed a solvent evaporation-induced self-assembly method to produce SHS with facile prepared, environmentally friendly, ultrafast ambient temperature curable properties. In this study, a new category of silicone-urea copolymers was synthesized via step-growth polymerization of polydimethylsiloxane (PDMS) and different diisocyanates. The SHS induced by the microphase separation and solvent evaporation was then fabricated by spraying these copolymer solutions onto various substrates. It was discovered that the surface superhydrophobicity and morphology can be readily tuned by varying the spraying concentrations, diisocyantes, solvents, spraying heights, and molecular weight of PDMS. And those synthesized copolymers were assembled into micrometer-size fibers or spheres consisting of hierarchical microstructure using tetrahydrofuran as spraying solvent and 10–15 cm spraying height, and the contact angles of surfaces reached 119° and 153°, respectively. To further explore the possible formation mechanism of the SHS, small-angle scattering, and X-ray photoelectron spectroscopy were carried out to investigate the effects of the microphase separation and solvent evaporation. With the induced microscopic roughness caused by the copolymers, these prepared super-anti-wetting surfaces have been demonstrated for potential utilization in the field of waterproofing, self-cleaning, and antifouling aspects. This work provides an effective way for the potential large-scale preparation of superhydrophobic surfaces with environmentally friendly materials and straightforward techniques.