A HYDROPHILIC/HYDROPHOBIC COMPOSITE STRUCTURE FOR WATER HARVESTING FROM THE AIR

The purpose of this study is to improve the water harvesting capacity of the traditional wire mesh from the fog by modifying its surface using a nature-inspired composite structure consisting of hydrophilic and hydrophobic zones. Hydrophilic zones were obtained by electrospinning or electrospraying of the polyamide 6 (PA6) / chitosan (CH) blend, and similarly hydrophobic zones were attained by electrospraying of polycaprolactone (PCL). The water harvesting capacity of the resulting meshes was tested and compared with each other. The highest water harvesting capacity was achieved with the PA6/CH nanofiber coated wire mesh as 87 mg / cm2/h. This mesh collected twice as much water compared to the uncoated mesh. However, its water collection rate decreased when nanofiber surface reached the saturation level. The addition of hydrophobic PCL particles onto nanofibers reduced the amount of water captured. In this case, the water collection rate of the mesh continued to increase.