Clean Coloration and Antibacterial-Finishing of Angora Wool Fabric Using Natural Dye-Aided Tannic Acid Mordanting by Electrospray

Abstract

Currently, the dyeing processes between natural fibers and dyes heavily rely on inorganic electrolytes, posing significant challenges to ecological and sustainable development. In this work, zinc ion was used to modify the surface of Angora wool through high-voltage electrospray technology (HVET), aiming to enhance the binding capacity with natural dyes. The optimized zinc ion dosage and the treatment voltage have been explored and determined as 6% o.w.f and 25 kV. In addition, tannic acid, as a mordant, was implemented to achieve the complete coordination of metal ions while also imparting antibacterial properties to the fabric (above 90% of bacterial reduction). Thanks to the synergistic effect between zinc ions and tannic acid, the dyeing performances of modified Angora wool has been significantly improved. Density functional theory (DFT) calculations further support that the introduction of zinc ions enhances the reactivity of the modified fibers and lowers the energy barrier of dyeing reactions. The dyeing rate, the dyeing depth, and the dyeing fastness of the modified fabric/gardenia yellow dyes optimized can reach to 66.9%, 4.7, and grade 4–5, which is much better than untreated fibers.