Biomimetic metal surfaces inspired by lotus and reed leaves for manipulation of microdroplets or fluids

Smart surfaces that can manipulate droplets or fluids have attracted intense attention because of their essential application prospects. However, it is still a challenge to obtain multifunctional integrated metal platforms that can simultaneously manipulate water/oil droplets and water/oil fluids. Here, inspired by the structure and wettability of natural reed leaves and lotus leaves, dual biomimetic platforms with switchable and anisotropic/isotropic wettability were prepared on copper by laser processing, chemical etching, and mixed thiols modification. The wettability of the integrated platforms can respond to the change of external pH value and reversibly switch between superhydrophobicity and underwater superoleophobicity. The areas of "reed leaf" structure and "lotus leaf" structure on the biomimetic platform have anisotropic and isotropic wettability, respectively. Significantly, by rationally designing the distribution of bionic structures, the dual biomimetic platforms can simultaneously manipulate water/oil droplets and water/oil fluids. This work not only provides advanced integrated biomimetic platforms and interesting design strategies, but also has important reference value in the development of new metal microfluidic devices.