Relationship between anti-felting properties and physicochemical properties of wool fibers treated with Ar-plasma

The anti-felting mechanism of plasma-treated wool was investigated by analyzing the surface of Ar-plasma-treated wool using XPS. The changes of single fibers and the properties of their assemblies were also studied. It was suggested that intermediate cystine oxides, i.e., S(O)-S and S(O)(2)-S groups generated on the wool fiber surface, have a strong affinity with water. In addition, carboxyl and sulphonic acid groups produced on the fiber surface during plasma treatment may also increase surface hydration and thus may play some part in the felting behavior of wool fiber. Subsequently, cohesive force is exerted by hydrogen bonding between these groups and water molecules on the fiber surfaces. This interaction results in a decrease in the flexibility of the individual fibers in the assembly. This limits the unidirectional movement of the fibers and thus improves the anti-felting behavior of the wool fibers.