Bioinspired anisotropic surfaces with hybrid wettability for enhanced fog harvesting

Water scarcity poses a growing global challenge, and atmospheric water harvesting has emerged as a promising decentralized solution. Bioinspired surfaces with hybrid wettability have shown potential for fog collection, yet most existing designs suffer from trade-offs between droplet condensation and removal, limiting their overall collection efficiency and long-term durability under real-world conditions. Moreover, the integration of anisotropic droplet transport to accelerate surface refreshment remains underexplored in a single, scalable platform. Inspired by the dorsal bumps of desert beetles and the micro-grooved structures of rice leaves, here we fabricate a bioinspired surface featuring both hybrid wettability and structural anisotropy (HWSA) using accessible electrochemical deposition, hydrophobic modification, and spray-coating techniques. The protruding hydrophilic particles accelerate droplet nucleation and growth, while the anisotropic hydrophobic background promotes rapid, directional droplet shedding to continuously refresh the collection area. Consequently, the HWSA surface achieves a maximum fog-collection rate of 4.3 g cm^-2 h^-1 and retains stable performance across 20 operational cycles. Furthermore, the surface displays exceptional self-cleaning capabilities, offering a durable and scalable solution for practical atmospheric water harvesting in resource-scarce environments.