Efficient Production of Bioinspired Multimaterial Multiscale Structures for Fog Harvesting

Abstract The global scarcity of freshwater resources continues to intensify due to the combined impacts of climate change, urban development, and population growth. Among emerging water capture technologies, fog harvesting, a passive process that condenses microdroplets from air, has gained increasing attention as a sustainable solution, particularly in arid and coastal regions. Nature provides efficient models for this process through organisms such as cacti, Namib Desert beetles, and spider silk, whose micro- and nanoscale surface architectures facilitate directional droplet capture, coalescence, transport, and collection. In this study, we present a single-layer photopolymerization (SLP) platform for the rapid and versatile fabrication of bioinspired fog-harvesting surfaces. Unlike conventional microfabrication approaches, SLP employs digital light projection to fabricate films containing complex bioinspired microstructures in a single exposure step, eliminating time-intensive layer-by-layer processing while maintaining high structural fidelity and surface reliability. Inspired by natural systems, a three-level hierarchical architecture with varying topologies and material distributions was designed for fog-harvesting applications. By integrating geometric features such as cones and grooves with hydrophobic and hydrophilic materials, the fabricated film promotes directional water transport through combined geometric and surface-energy gradients. Experimental results show that fog collection efficiency can be readily tuned by adjusting geometric parameters and hierarchy levels, leading to an overall performance improvement exceeding 440%. These findings demonstrate that single-layer photopolymerization offers a promising, scalable manufacturing strategy for nature-inspired fog-harvesting systems suitable for deployment in remote or resource-limited environments where conventional water access is limited.