An Efficient Fog Collection Origami Janus Membrane for Rapid Directional Water Transport and Omnidirectional Fog Harvesting

Existing Janus fog harvesting technologies struggle to achieve efficient and continuous fog collection across various fog flow directions. In this work, we developed a Janus fog harvesting (JHL) system, characterized by a boundary-free Janus system formed by selective modification with octadecanethiol, creating a pair of hydrophilic and hydrophobic domains. The system features a 3D origami macrostructure composed of scallop arrays and shaped like an improved trumpet flower. The wettability gradient Janus system enables rapid droplet capture and ultrafast absorption. The multiple parallel and dual-asymmetric 3D Kirigami superhydrophilic channels facilitate high-speed, directional, and long-range liquid transport. These mechanisms work seamlessly together to keep both the superhydrophilic and hydrophobic surfaces dry at all times. As a result, our JHL achieves a fog harvesting efficiency as high as 0.83 g·cm^-2·min^-1, which is 3 times that of the original sample. Moreover, our improved trumpet-shaped 3D structure extends the Janus design concept from traditional membrane materials to spatial membrane configurations, making it suitable for omnidirectional fog harvesting in any fog flow environment.