Conductive\nSuperhydrophobic Smart Coatings Based on\nSpherical Silver Nanoparticles and Waterborne Polyurethane for Flexible\nand Wearable Electronics

The\ndevelopment of flexible smart conductive fabrics is crucial\nfor applications in smart healthcare and signal transmission during\nhazardous rescue operations. However, environmental challenges such\nas moisture, dirt, mechanical abrasion, and bacteria can significantly\nimpair their electronic performance. Herein, we introduce a novel\ntwo-layered coating strategy that integrates silver nanoparticles\n(Ag NPs) and modified silica nanoparticles (QSi) with waterborne polyurethane\n(WPU) to develop multifunctional superhydrophobic conductive coatings.\nThe inner composite layer, combining WPU with Ag NPs, guarantees high\nconductivity (5.22 S·cm<sup>–1</sup>) and mechanical durability.\nThe outer shell layer, created by spraying a mixture of WPU and QSi,\nprovides a robust superhydrophobic barrier, maintaining a water contact\nangle above 150° and resistance below 80 Ω even after 200\nkneading cycles. Additionally, the coated fabric exhibits satisfactory\nself-cleaning, antifouling, low water adhesion (32.95 μN), drag\nreduction (supporting approximately 11 times its weight on water),\nand appreciable antibacterial activity (>99.99%), ensuring its\nlong-term\nstability in harsh conditions. By integrating conductivity with superhydrophobicity,\nflexibility, and wearability, this smart fabric presents a promising\nstrategy for precise underwater detection, such as monitoring swimming\nmovements or finger bending, while also offering safety alert signals\nin challenging wet environments.