Magnetically aligned blue light curable superhydrophobic films for advanced textile applications

Herein, a superhydrophobic coating layer with a rough microscale/nanoscale structure is prepared using magneto assembly and photocuring polymerization. In particular, specifically, modified hydrophobic carbonyl iron powder (CIP) serves as the filler for magneto assembly to construct the rough surface, while a photoinitiator system, organosilicon-modified polyurethane acrylate (PUA) and hydroxyethyl acrylate (HEA) monomer form the polymerization system for magneto-photocured coating films. Contact angle measurements and SEM images reveal that CIP aligns and aggregates along magnetic field lines, leading to a ‘mountain peak’-shaped micro/nano rough surface. At 100 wt.% CIP loading relative to the polymerization system, the coating achieves a 156.7° contact angle and 5° sliding angle, confirming superhydrophobicity. Using a simplified surface structure model and simulation experiments, this study suggests that greater height to width ratios and smaller spacing to width ratios are beneficial for preventing liquid droplets from penetrating into the depressions of the ‘mountain peak’-shaped surface structure. The simulation also provides physical insight into the surface wetting behavior toward the Cassie state, with the surface contact angle reaching 150° for the best performing structure. Fabric coated with a 150 μm-thick film (200 mT magnetic field) exhibits 155° contact angle, 5.5° sliding angle, reduced adhesion and moderate self-cleaning performance, showing application potential for barrier-type technical-industrial textiles.