超疏水高分子材料表面的微结构设计及其可调的粘附性

he microstructures in the templates are replicated on the surfaces of large-sized polypropylene samples using microinjection-compression molding in one step. The surfaces molded via the two sieves with different meshes exhibit the dual-level microstructures, which consist of micro pyramids with high aspect ratio and micro ridges. The surfaces molded via four templates, which consist of the aforementioned two sieves stacked with punched plates with different hole diameters, exhibit the three-level microstructures, which consist of the uniformly distributed micro columns and the aforementioned dual-level microstructures on the top surfaces of the micro columns. The all six surfaces have the static contact angles of above 150 (i.e., exhibit superhydrophobicity) and the rolling angles of from 5.5 to more than 90 (i.e., exhibit a wide range of manipulation for the adhesion). For the surface having small-diameter micro columns and a few micro pyramids and micro ridges on their top surfaces, the water droplet forms a global non-composite state, thus high adhesion appears (the petal effect). For the surface having small-diameter micro columns and a number of micro pyramids and micro ridges on their top surfaces, the water droplet forms a localized non-composite state, thus relatively high adhesion appears. For the surfaces having the dual-level microstructures or having large-diameter micro columns and a number of micro pyramids and micro ridges on their top surfaces, the water droplets form a global composite state, thus lower adhesion appears; especially, the surfaces having small-sized micro pyramids and narrower gaps between the micro pyramids exhibit low adhesion (the lotus-leaf effect).