Improved interfacial floatability of superhydrophobic/superhydrophilic Janus sheet inspired by lotus leaf

Interfacial materials exhibiting superwettability have emerged as important tools for solving the real-world issues, such as oil-spill cleanup, fog harvesting, etc. The Janus superwettability of lotus leaf inspires the design of asymmetric interface materials using the superhydrophobic/superhydrophilic binary cooperative strategy. Here, the presented Janus copper sheet, composed of a superhydrophobic upper surface and a superhydrophilic lower surface, is able to be steadily fixed at the air/water interfaces, showing improved interfacial floatability. Compared with the floatable superhydrophobic substrate, the Janus sheet not only floats on but also attaches to the air–water interface. Similar results on Janus sheet are discovered at other multiphase interfaces such as hexane/water and water/CCl₄ interfaces. In accordance with the improved stability and antirotation property, the microboat constructed by a Janus sheet shows the reliable navigating ability even under turbulent water flow. This contribution should unlock more functions of Janus interface materials, and extend the application scope of the binary cooperative materials system with superwettability.