Bioinspired Double-stranded Yarn with Alternating Hydrophobic/Hydrophilic Patterns for High-efficiency Fog Collection

Efforts to develop innovative water harvesting strategies offer powerful solutions to alleviate the water crisis, especially in remote and arid areas. Inspired by the hydrophobic/hydrophilic pattern of desert beetles and water self-propulsion property of spider silks, a double-strand hydrophobic PVDF-HFP/hydrophilic PAN nanofibers yarn is proposed by electrospinning and twisting techniques. The double-strand cooperation approach allows for water deposition on hydrophobic PVDF-HFP segment and transport under the asymmetric capillary driving force of hydrophilic PAN segment, thus speeded up the aggregation and growth of droplets. The effects of the composition and the diameter ratio of the two primary yarns were studied and optimized for boosting fog collection performance. The double-strand anisotropic yarn not only provide an effective method for water harvesting, but also hold the potential to inspire innovative design concepts for fog collection materials in challenging environments.