Surface polarity control of flyknit upper fibers via plasma technology and adhesion with waterproof coatings

To address the issues of insufficient interfacial adhesion between polyester/nylon fibers and waterproof coatings in fly-woven shoe uues and the imbalance between waterproofing and breathability, a precise regulation scheme for fiber surface polarity based on low-temperature plasma technology was proposed. Three groups of waterproof coating-fiber composite samples, namely unmodified, moderately modified, and over-modified, were prepared by setting different plasma treatment parameters (flow rate, power, and time) with oxygen as the gas source. The modification effects were analyzed through various performance tests. The results show that the moderately modified samples form suitable roughness and polar functional groups on the surface. The hydrostatic pressure is increased to 35.83kPa, the air permeability is maintained at 7.46 mm/s, and the quality factor reaches a maximum of 0.334. At the same time, it performs well in terms of wear resistance, antibacterial properties, and low water absorption rate. This shows that the synergistic effect of plasma modification and polar coating can enhance interface bonding, providing theoretical and experimental support for optimizing the waterproof coating process for flying fabric shoe uppers.