Wettability gradient of photoresponsive electrospun yarns for harp-based fog water harvesting

Fog water harvesting offers a solution to water scarcity. Here, we introduce a method to enhance fog water harvesting systems utilizing electrospun yarns featuring a wettability gradient. These yarns, made from polyvinylidene fluoride (PVDF) and titanium dioxide (TiO2), gain photoinduced hydrophilicity under UV light due to TiO2 photocatalytic properties, allowing dynamic shifts from hydrophobic to hydrophilic states. Experiments show that an alternating PVDF-TiO2 harp with a wettability gradient surpasses purely hydrophobic or hydrophilic versions in fog collection. The strategic mix of hydrophobic and hydrophilic sections enhances droplet movement and water capture, achieving a 16% increase in collection rate up to 400 mg cm−2 h−1. This approach introduces a novel method for creating wettability gradients in electrospun yarns via UV irradiation and represents a significant advancement in adaptable fog water harvesting systems. [Display omitted] •Enhanced fog water harvesting using electrospun yarns with a wettability gradient•Dynamic adjustment from hydrophobic to hydrophilic via UV irradiation and heat•PVDF-TiO2 yarns made by electrospinning form porous fibers for fog collection•Alternating yarns outperform just hydrophobic/hydrophilic, reaching 400 mg cm⁻2 h⁻1 Fog water harvesting can address water scarcity in arid regions. This study by Parisi et al. introduces electrospun PVDF-TiO2 yarns with a dynamic wettability gradient, enhancing fog collection. This approach uses electrospun yarns to capture water with harp-like structures, offering scalable, efficient water harvesting solutions and providing viable, accessible water.