A review on tackling global water scarcity through biomimetic microstructures in fog harvesting devices

The latest State of Global Water Resources highlights the urgent challenge of global freshwater shortages. Addressing this challenge requires effective water harvesting technologies. Among various approaches, fog harvesting is highly valuable, but geographically constrained by fog frequency, wind regimes, and liquid water content. Thus, it primarily serves as a decentralized or supplementary water source for fog-rich, infrastructure-limited regions. Operating within this specific environmental deployment window, bio-inspired fog harvesting devices (BFHDs), mimicking organism surface features, offer a viable localized solution to water scarcity. This review delves into the latest advancements in BFHDs. It elucidates the foundational principles of water droplet behavior and examines the crucial functions of biological surface microstructures during water capture. This review traces the evolution of BFHDs from one-dimensional to multi-dimensional designs, and from single to multiple bionic structures, and correlates structures with corresponding fog harvesting performances. Additionally, attention is drawn to multifunctional devices integrating fog harvesting with triboelectricity and desalination. Finally, this review tackles current research challenges and offers insights into future directions and technical barriers in the progression of BFHDs.