Biomimetic fabrication of micro-/nanostructure on polypropylene surfaces with high dynamic superhydrophobic stability

Recently, the biomimetic replication of micro-/nanostructure present on lotus leaves has attracted great interest. Unfortunately, the nanostructure on the surfaces of lotus leaves, which play a critical role in making them superhydrophobic and self-cleaning, are difficult to precisely replicate. Herein, a nickel replica is fabricated by electroless plating and electroplating with natural lotus leaf as natural template. Using the nickel template, lotus leaf-like structure is fabricated on polypropylene (PP) surfaces by injection molding, an industrially feasible technique for fast mass-fabrication. It is demonstrated that the micropapillae on the lotus leaf are successfully fabricated on the PP replica, especially nanohairs with sharp tips and high aspect ratio are developed without additional surface coating or chemical modification. The PP replicas exhibit a highly similar wettability with the lotus leaf. More interestingly, the nanohairs on the PP replica are superior to the nanotubules on the lotus leaf in terms of the dynamic superhydrophobic stability and superhydrophobic thermal durability. Impact droplet exhibits shorter contact time on the PP replica than the lotus leaf. Mechanisms for the functionalities of the nanohairs on the PP replica are analyzed. Such superior properties are expected to have industrial applications, such as anti-icing, microdroplet transfer, and self-cleaning.