Wet Chemical‐Assisted 3D Printing Multiple Biomimetic Structural‐Wetting Dual‐Gradient Material for Efficient Fog Harvesting

Abstract Collecting water from the atmosphere is an effective method to alleviate water scarcity. Efforts to enhance fog harvesting focus on optimizing three key processes: fog capture, droplet condensation, and droplet transportation. Inspired by spider webs and cactus thorns, this study used photo‐stereolithography 3D printing technology to fabricate a bionic fog harvesting web (FHW) with a primary spindle‐shaped web, secondary conical long thorns, and tertiary micro inverted cone thorns. After wet‐chemical mask modification with silica sol coatings, the desert beetles‐inspired biomimetic FHW with the structure‐wettability dual gradient is fabricated. The influences of the structure parameters including conical angle, arrangement orientation, spike density/angle, wettability gradient, and windward angle on fog harvesting performances are systematically investigated. Moreover, an integrated fog harvesting device (FHD) is designed and fabricated using fused deposition modeling 3D printing technology, which can simultaneously realize efficient fog harvesting, stable water storage, and controlled water extraction. The outdoor actual fog harvesting efficiency reached 981.7 mg cm ^{− 2} h⁻¹, and the water retention rate under high‐temperature sunlight reached 96.52%. Therefore, this work enhances the understanding of super wetting interfacial fundamental theory and provides valuable strategies for designing and fabricating efficient and systematic water collection devices.