A novel ultra-hydrophobic surface: Statically non-wetting but dynamically non-sliding

In this study, we report the fabrication of a novel surface with both morphology and composition heterogeneities by casting polymer blend solution. The resultant poly (methyl methacrylate) (PMMA) and amphiphilic polyurethane (A-PU) surface has a rough structure on microscale and separated hydrophobic and hydrophilic nanodomains as well. On this surface, water drop shows a static CA about 160 degrees but the drop is pinned on the surface at any titled angles. This phenomenon can be ascribed to the special surface characters as the air trapped in the porous surface and hydrophobic domains repel the water, leading to a very high static CA, whereas the hydrophilic domains contacting with water at the interface, though being restrained to a little fraction by the surface roughness, adhere the drop. In addition, by adding the third component, hydrophobic fluorinated polyurethane, in the blend, the formed PMMA/A-PU/F-PU blend surfaces show CA about 160 degrees but the SA be able to rationally tune from small to large by adjusting the ratio of A-PU to F-PU. Our method provides a novel approach for controlling surface morphology, composition and corresponding surface adhesion, and may find many applications in various fields.