Bioinspired Janus Triboelectric Surface Enabled by Laser-Patterned Oxidation

Amid growing resource scarcity and sustainability demands, water vapor emitted from cooling towers is shifting from a neglected industrial byproduct to a strategic water resource, yet its efficient recovery and accurate monitoring remain challenging. Inspired by the hydrophobic-hydrophilic duality of <i>Alocasia macrorrhizos</i> leaves and the asymmetric geometry of cactus spines, a bioinspired Janus triboelectric surface (BJTS) was designed. The bottom layer enables water vapor collection, while the top layer facilitates signal sensing. By arranging the BJTS vertically in a staggered pattern, direct water vapor condensation is combined with droplet-induced contact electrification, enabling simultaneous collection and real-time sensing of water vapor. This integrated system enables detection of water vapor temperature and flow rate, with a machine-learning-assisted recognition accuracy of 98.2%. Overall, this work paves the way for simultaneous water resource recovery and precise real-time monitoring.