Bioinspired hierarchical colloidal crystal paper with Janus wettability for oil/water separation and heavy metal ion removal.

Increasing attention has been paid recently to superwettability and its prospective potential applications in various fields. A new approach towards the establishment of flexible, self-assembled superhydrophobic surfaces with self-reported wettability on a variety of substrates has been advanced. The approach involves the fabrication of a dense monolayer of photonic crystal films that possess a layered structure with superior adhesion at the liquid-gas-solid interface. Thus, the resulting hierarchical photonic crystal film with a structurally hydrophobic surface offers a promising addition to the creation of durable and flexible superhydrophobic surfaces across a variety of substrates that exhibit the self-reported wettability. Furthermore, a bifunctional membrane that can effectively remove oil and adsorb heavy metal ions contained in wastewater has been developed for potential use in large-scale industrial wastewater treatment. This research sheds fresh light on the application of bionics and the lotus and mussel functions in oil/water separation.