Continuous Fabrication of Parallel Micro-Sheet Decorated Fibers for Ultrafast Fog Harvesting

Uneven fibers decorated with micro-patterns on their surface have drawn more interest due to their fascinating properties. Aligned micro-patterns parallel to the fiber's axial direction have been easily fabricated because of the directional stress that is strictly parallel to the fiber's axial direction induced by thermal-drawing or melt spinning, whereas continuous fabrication of micro-patterns perpendicular to the fiber's axial direction remains a huge challenge. In this work, the extrusion molding method is employed to continuously fabricate HDPE fiber decorated with parallel micro-sheets (HFPS) yet perpendicular to the fiber's axial direction. These plate-like micro-sheets' spacing, thickness, and height are in micron-scale, on which there exist numerous lamellar crystals in nano-scale. The as-fabricated fiber shows excellent hydrophobicity, high adhesion to water as well as long-term underwater repellency. More interestingly, upon a certain strain, plate-like micro-sheets can be transformed into S-shaped (HFSS) ones but still parallel with each other. Compared with the reported uneven fibers decorated with micro-patterns, such fiber shows the ultrafast fog harvesting (10.3 g·cm^-2·h^-1). This work follows the concept of "functionalized processing for thermoplastics" to continuously fabricated thermoplastic fiber decorated with parallel micro-sheets perpendicular to the fiber's axial direction, offering new prospects for expanding the application scope of thermoplastics.