Ultrashort-Pulsed Laser Modification for Highly Hydrophobic Woven Fabric

Among superhydrophobic materials, non-wettable textiles arguably come in contact or interact with the human body most frequently.The author presents the proof-of-concept of a novel modification method for a woven fabric surface for realizing excellent hydrophobicity using two kinds of ultrashort-pulsed lasers.The key hypothesis is that to improve the hydrophobicity of the woven fabric, it might be necessary to not only improve the water repellency of the surface but also to prevent liquid seepage between filaments of the woven fabric.A woven fabric of Nylon 6 is addressed by (a) enhancing liquid hydrophobicity by applying micro-periodic structures on the filaments through a femtosecond-pulsed laser processing based on the Cassie-Baxter model, and (b) preventing liquid seepage between the network of filaments by utilizing picosecond-pulsed laser processing via thermal sealing.The optimal conditions for the laser processing were determined experimentally.This laser modification method exhibited an apparent contact angle of 120, comparable to chemical treatments as a non-wettable application.A processed depth that was onefiftieth of the filament diameter was sufficient for improving the hydrophobicity of the woven fabric.The combination of laser processing effectively enhanced the water repelling and sealing of the woven fabric, indicating that excellent hydrophobicity was achieved.No significant difference was observed in color due to the laser processing, and the decrease in tearing strength was approximately 9%.These results highlight the possibility of strategies that can introduce a novel process for non-wettable woven fabrics as a sustainable technology.