Advances in materials for fog harvesting: A comprehensive review of conventional, bioinspired, and advanced functional materials

Water scarcity is affecting many nations worldwide, and countries including Jordan, Saudi Arabia, and India are among those affected.Fog harvesting has emerged as a promising passive approach for atmospheric water collection, particularly in arid and semi-arid regions where conventional freshwater resources are limited.The performance of fog-harvesting systems is strongly governed by the material, surface and structural characteristics of the collector, which determine fog-droplet interception, adhesion, coalescence, transport, and drainage.Over the past two decades, research has progressed from conventional mesh collectors toward engineered materials and bioinspired surfaces designed to overcome the limitations of conventional systems.This review provides a comprehensive assessment of materials used for fog harvesting, covering developments from 2006 to 2026.Conventional metallic and polymeric meshes, including stainless steel, aluminum, copper, polyethylene, polypropylene, and nylon, are first reviewed in terms of their material properties, wettability, durability, cost, and water-collection performance.The review then examines advanced material strategies, including surface coatings, hydrophilichydrophobic patterns, superhydrophobic and superhydrophilic surfaces, electrospun nanofibers, and micro/nanostructured surfaces.Particular attention is given to bioinspired materials and architectures derived from cactus spines, spider silk, Namib desert beetles, and pitcher plants, as well as emerging fractal and triply periodic minimal surface (TPMS) structures.The comparative analysis demonstrates that material performance cannot be evaluated solely on fog-droplet capture; efficient water harvesting requires a balance between capture, droplet mobility, coalescence, shedding, drainage, mechanical stability, environmental durability, and manufacturability.The review identifies the transition from passive interception-based meshes toward multifunctional, surface-engineered, and bioinspired materials as a major technological development in fog harvesting.